Yes it's a bad idea. Everyone should just think individually; "is this fiction working for me personally?" If the answer is no, then you shouldn't support it. If the people from some other organized group which "threatens you" are so brainwashed that they think they benefit from their humongous group (when in fact, they're just treated as a meaningless, tiny number), then you may have to bare the pain of their idiocy for a few generations or so until their masters exploit them out of existence. It's an unfortunate situation. The sheep get slaughtered, but unlike sheep, you can't force the sheeple to breed; and they don't; deep down they know how miserable their existence is.

In reality, the group has little power over you as an individual. It derives most of its power from your own compliance. The compliance of others is a lesser factor in your oppression.

You don't need to believe in alternative fictions unless you created it. You just need to wait it out and pretend hard! Create your own fiction, exploit every loophole! Let the idiots realize their idiocy on their own and rebel on their own later once they realize they were fooled. You have to be a radical realist, wait it out and bare all the costs in the meantime. It's better to bare the pain of system dysfunction for decades than to go along with it and find yourself at the front of the firing line later, fighting against what you helped to create.