Not going to gaslight you and say no one is making those comments, I'm sure they are. That said, there are millions of people in the world who don't give a fuck about gen z fashion, or who aren't rude, and then there are millions of people who are dicks, or insecure about their own appearance or place in the world.
As a millennial I remember the manufactured controversy between boomers and millennials, and similar comments about appearance, work ethic, etc. Now that millennials are "old" some of them see new stuff coming along and feel compelled to complain. Whatever age group someone belongs to they'll complain about things they see, age related or otherwise, so I wouldn't focus too much on it.