In addition to other comment, first he’s been their “elected” supreme leader for so long, that a lot of young people never knew anything different. It’s like domestic violence, if a child is being regularly hit and so all his friends, the child learns that this is how things should be. Second, by completely controlling media putler created and maintains political apathy (it was already strong in ussr), so even if they don’t like something, they know very well that there’s nothing they can do.