Three things.
First, you're echoing a lot here what I said about the x-card - so I have to agree. I'd like frame it a little differently though: normally the GM is responsible for running the game and keeping things on track. That means he is also responsible for balancing out any conflicting interests of participants (arachnophobia versus drow campaign). What I am seeing in the x-card (and probably also the consent form) is an attempt to err on the side of caution by giving each participant a veto right. While well-intentioned it opens up a potential new aventue for abuse. And that, in short, is why I reject this new model and remain in favor of the GM being the final arbiter of things. And walking out if you're not liking how things are being handled by him has always been an option, I don't think anyone needs to be reminded of that. (But if the underlying intention is to give insecure people enough confidence to actually take that step of walking out, I'm fine with that message.)
So, in short, the effort to remove any insecurity over the GM being in charge of the game falls short. Instead, interests need to be balanced on a case-by-case basis. X-cards and consent forms don't do the necessary individual balancing act and therefore are failed attempts at improving the game.
Secondly, writers, filmmakers, comic book authors don't put up a lot of information what to expect from their creative works in advance either. You quickly get a sense what to expect in Game of Thrones but not much advance warning. In RPGs, it should be enough to give a quick campaign outline and maybe something like "18+ content". You have no right for more information from me just because I don't have the same clout as HBO.
Thirdly, I think you may have it a bit backwards about destroying western norms, Pundy. This isn't the goal; it's means to an end. Remember what I said about the left's Robin Hood syndrome? Muslims are the "intended" victims (as in: intended for the victim role), the poor downtrodden widows and orphans, while western conservatives are intended for the role of the Sheriff of Nottingham. That's why whatever wrong muslims do gets rationalized whereas the same thing coming from a western conservative is an act of pure evil. Indeed proof that conservatives are evil by nature.
The end goal is to feel both intellectually and ethically superior your conservative neighbor (or rather those stinking smalltown USA peasants). Destroying western civilization is just means to an end, the end being feeling a hero for saving innocent people from oppression by the evil conservatives. Or the dying planet from evil businessmen,
It's my working hypothesis that they take it to such extremes because most of them see no realistic pathway to a sense of superiority within the system.