I don't get the 'classist' argument at all. You don't need to be rich to want to stop doomscrolling, or to put your phone down for an hour. It sounds more like the kids who call it 'classist' understand phone addiction but don't want to face the fact its actually bad for them... like when an overweight person says 'Id rather enjoy life than eat that salad, I bet that in-shape person is a bore to be around!"
Oh, absolutely. When I was a teen, you'd be called some sort of homophobic slur for refusing to go along with the current zeitgeist. Now, it's more effective to force conformity by calling people classist/racist/etc., and the kids know it too.