Your question is a valid one, but it's not limited to the last 10 years, nor is it limited to Eretz Yisroel.
The Ben ish Chai in Teshuvos Rav Pealim was asked about something written in the Teshuvos of the Bais Yosef about the Arzai. The Ben ish Chai says the Bais Yosef was misinformed by a Shliach regarding what the Arizal holds. When asked how this is possible, seeing that the Bais Yosef was such a Godol as well as a Baal Ruach haKodesh, the Ben ish Chai responded that that is not a valid objection, because Gedolim - even neviim - can and have been misinformed. Why not? All you have to do is give them false or mistaken information.
I'd like to add that besides all of the above, the Bais Yosef and Arizal were neighbors as well. Nevertheless, the Bais Yosef wrote in his Teshuvos that what the Arizl said was incorrect, based on, according to the Ben ish Chai, a misrepresented version of what his neighbor, the Arizal, had said.
It happens. Elisha was fooled, Yitzchok Avinu was fooled. It happens.
Rav Chaim Ozer wrote a letter opposing a united rabbinic organization on the grounds that the secretaries often misrepresent the members of the Moetzes. He says that he learned this "from experience."
The Satmar Rebbe in Vayoel Moshe cites some bad Hashkafos that were disseminated by the Agudah, and he says when he asked the Agudah Gedolim about it, some of them even said it was Apikorsus, in any case all of them agreed it was wrong, but they said what can they do - the Askanim didn't ask them before they took it upon themselves to represent the Agudah on their own. (It appears from another source that at least one Godol he was referring to then was Rav Yaakov Kaminetzky).
It happens all the time. I know about the Rav Elyashev human-hair shaitel situation you mention, because I was the one who gave Rav Elyashev his information - the first time. I was the one who asked him that shailah and his first teshuva was in response to it. Years later the facts he received were mistaken. Rav Feivel Cohen went to him after he prohibited the shaitlach based on the second (wrong) set of facts, saying that we know he was misinformed, and Rav Elyashev said to him basically that he's not the FBI (of course I'm paraphrasing here) and that if we know the facts to be different that what was presented ot him then of course we should follow what we know and not what he paskened.
When I was in 12th grade, there was a letter printed in the Jewish press from Rav Moshe recommending that people should attend a certain event. When we confronted out Rebbi, who was also our Menahel, about it (he prohibited us to go) he went to the Rosh Yeshiva (Rav Hutner) who called Rav Moshe who told him that he wrote that letter for a totally different event and someone (I know who but it doesn't matter ho he is) took it upon himself to decide that the letter also applies to the event in question, and so printed the letter without the permission of Rav Moshe. Rav Moshe did not recommend going to that event.
Rav Avigdor Miller (Q&A vol. 2) complains about a certain frum organization (it's obvious who he is referring to) who have a rabbinic group that they consult, but they ask their questions in a way that maximizes the chances of getting the answer they want, as opposed to the real opinion of their rabbonim. They first decide on a plan of action, then say something to the effect of "We plan on doing such-and-such, is there a problem?" Add to that if they say they already made plans and set things up, and now they come and ask if they have to undo all their plans or if it is OK for them to continue. Of course, undoing what theyve done so far would involve a lot of time money and effort, and then there would be no other approach that they could take because by that time it would be too late to do anything, plus the "Baalei batim" would maybe not support any other approach, etc etc etc etc. Then The Rav may then say OK then do it. Obviously, that's a sneaky way to get the public to think that the Rav being asked actually thought what they are doing was what they לכתחילה should be doing.
It's quite simple: Someone can go to the Chofetz Chaim and ask him what to do with his milchige dish that he washed with a felishige sponge, and whwn he tells his wife the psak shell correct him: But it was a milchige sponge, not fleishg. Then the husband says "But I got a psak from the chofetz chaim!" Do you think that in such a case there is any hava aminah that the wife should follow that "psak"? Or that the Chofetz Chaim should have first "investigated" to see if the sponge was in fact used for milchigs or felishigs?
It happens all the time. It's quite simple. Gedolim, poskim, rabbonim, can only base their decisions on facts presented to them. Like doctors. Or lawyers. Or anyone.
There is nothing to do about that except to be educated on your own so that when a Godol seems to say something that does not make sense - such as Rav Moshe's "letter" about the above mentioned event - you'll start asking questions. You need to learn the Sugya if youre going to try to understand whats going on, as opposed to just following some Kol Koreh. Listening to a Kol Koreh without knowing anything about the topic is, at the very best, like knowing the Psak of the Kitzur Shuchan Aruch without knowing anything about the Sugya. You may misunderstand what it says, you may misapply it, or you may get it right - maybe.
Rav Moshe stated many times that he did not intend his Igros Moshe to be used by people reading the last line alone. You need to read and understand the whole teshuva in order to understand it. otherwise, you may not correctly apply when where and to what his final psak applies.
When you find a statement of a Godol on a certain topic, if you are completely ignorant of the basic Halachah or Hashkafa surrounding the issue, if the Kol Koreh or letter or statement is all you know about the topic, you're very likely not going to understand what the Godol was really saying. See my article here about this. In short, it's about the "clear and explicit" letters that Gedolim such as Rav Chaim Kanievsky write apparently asking people to give Tzedaka to certain specific organizations, and if they do, they'll get some kind of Brachos.
Here's the rule: People who understand and issue based on Kol Korehs and statements of Gedolim are like people who start a Sugya with the Rav Shmuel Rozovskys without knowing the Gemora Rashi and Tosfos. Or like learning Halachah from a Kitzur without knowing the Gemora anf Shulchan Aruch. You're going to make mistakes. And youre going to misunderstand what the Kol Koreh says. And so, we have a Shulchan Aruch and Poskim telling us where our priorities in Tzadaka are, and Rav Chaim Kanievsky will not write any letters changing those priorities - signed documents notwithstanding. It is not going to happen. Clearly, whatever bounty Rav Chaim promised for people who give to whatever organizations he is writing about will also be granted to those who give to other euqally valid organizations. The inviolable, first-principle rule is: Jews follow shas and Poskim. No Godol is going to change that.
And so I wrote a letter to Rav Chaim asking him if someone simply follows the Shulchan Aruch and gives to whatever Tzedaka he wants - not the one specificed by Rav Chaim's letters - will he get the same Brachos as if he gives to the organizaiton specified by Rav Chaim.
His answer: אין צריך לברכתי
So we know two things so far: (1) The accuracy of a Teshuva depends on the accuracy of the shailah. How many times have you seen two people ask the same Rav the same question - or a Rebbi or a teacher - and received two different answers. The reason is because the question was asked 2 different ways. You want to be sure that the person who asked the question is (a) reliable and ( b.) accurately knows all the facts about the issues being asked about
And (2) you need to know the basic issues - Halachah or Hashkafa - that are involved in order to properly understand what the Psak says; in order to recognize a Psak that needs further clarification,; and in order to recognize a Psak that does not make sense and therefore should be suspected of being a distortion. I remember about 15 or so years ago there were "very reliable sources" saying in the name of Rav Shach that as a response to the suicide bombings in Eretz Yisroel that were taking place then, people should all start Shabbos 10 minutes earlier that week. The entire thing from the content to the way ti was conveyed did not make sense to someone even remotely familiar. Of course, it turned out to be false. Another example is that silly Dibbuk story.
Finally, the third thing to know (3) is what Shaya said above - and I cannot overemphasize this because this is usually the main reason people are confused: Do not get your information from blogs or Jewish websites or rumors in the street. Its not merely an issue of the consistent factual inaccuracies found in these places. It's also the spin, the agenda, and so many other factors involved. Anyone who gets their information from such blogs is דמו בראשו. He is handicapping himself from knowing what's really going on, and should not expect to know what anyone holds about anything. This is an important choice people must make. You can choose to live in the internet world of misinformation disinformation and distortions, but then don't expect to be anything except confused and disheartened when you acquire the false view that it's so hard to know what the truth is.
Now on to the protest, which is the issue being discussed.
(to be continued)