I've quit jobs and been laid off from jobs and I will admit that when I do, I always kind of hope that the company goes bankrupt the day after I leave because I was so important. Companies I've quit or been laid off have gone bankrupt, but it took years and sadly I don't think there's any way for me to draw a logical connective of "no tombert -> company fails".

I've never quit a company on purely ethical grounds, but I have turned down interviews and offers because of them. They're probably not going to go bankrupt just by not hiring me, but I like to think that making it incrementally harder to find talent slows down their progress of doing evil things, if only a little.

That's probably still a delusion of grandeur on my end, but we all should have an ethical line that we won't cross; most of us end up working for monsters and/or assholes, especially at BigCos, so your options generally boil down to "work for an asshole who's doing evil that you can live with" or "go live in a Unabomber shed". I guess it's important to make sure that "the evil thing you can live with here" isn't just any act of evil.