Most of the whining that "it's impossible to de-admin someone" means the complainant is upset that someone can't be deadminned because the complainant is upset, and there's all this *tedious procedure* to go through. In practice, it's easier now than it's ever been.
Yes, but the reason we make it quite difficult to desysop someone is because it's rarely necessary, since we are so careful not to promote anyone questionable. If we relax promotions, we would need to relax demotions too. And if we relax demotions, we would be able to relax promotions. It's rather circular, but the end result is that we have to do both at the same time for it to work.