This is just depressing, I was fine with the ending to ME3, though I've got my problems with it, I'm not going to sign any petitions. That said, some people were finding a productive way of airing their grievances and it sucks for them that they can't do that because of the ignorance of some within their ranks.
The whole conspiracy theory angle is awful as well, I would not be surprised if there's overlap between those who are asking for their donations back and those who think this was shut down by some shadowy cabal of journalists and corporations aligned to destroy them, personally. There's no conspiracy, don't be surprised that IGN writes crappy stories, they're IGN, that is what they do. Threatening to withhold future money from a good cause, as some in this thread have done, because they had to red-light something that was opening a bad door, is cartoonishly petty.
Let me just float my own personal reason for not demanding a new ending to ME3. First of all, Mass Effect has always been strongest when dealing with characters, that is BioWare's strong suit. The character moments in that game were worth the price of admission alone, and if you actually take the time to digest the ending on your own, I think most people will be fine with it, disappointed in some things, but largely okay with the experience.
So we've got a group of people who are saying, effectively (I'm being deliberately reductive because I want to match how it would sound to a writer) "No, you shat the bed, take it back. Don't get to work on a new project, you have to go and clean up your mess. For free, now. Do it, do it, and smile for daddy."
It shouldn't be surprising that the community of professional writers who cover these stories find your argument entitled. To them, this is the the height of entitlement. Its not that you're wrong, and its not that they're wrong, you're just all looking at this from different angles.
Finally, you've seen how fickle the gaming community can be, you know that if they change the ending a significant portion of you are still not going to be satisfied.
If they charge for it (which they will, after all they're not working for free here), a large and very vocal group will up the volume demanding that the price be removed, decrying it as an example of yet more EA/BioWare greed, etc.
Then there are the people who won't be satisfied with whatever BioWare does, because it won't match their very specific demands. They'll yell and complain that BioWare went too far or not far enough in any alterations.
Then there's always the possibility that if they cave and make it free, and if it satisfies everyone within your movement, you know that some BioWare apologists will yell about tyranny of the minority, a new, changed ending that they didn't ask for being foisted upon them because of a few malcontents.
And what if any new ending is worse than what they gave you the first time around? Are you going to ask them to change it again? At what point does this stop? Its entirely possible that this was the best they could do, not laziness just plain lack of ability, and they are fundamentally incapable of satisfying your complaints.
It is a no-win scenario, no matter what they do, and no matter what you do, the outcome is bad for both sides.