No one is complaining about AA tanks existing. It's more about their effectiveness. Where maps are so small, 1 AA tank covers like 75% of the map. You can jump in a Bradley, sit near your spawn and farm kills the hole match, without requiring any skill.
Bradley shouldn't paint targets either.
It also doesn't help that the only class effective against vehicles is engineer. No other class can do anything against them. This has forced half the team to play Engineer on vehicle maps. So now everyone is running round with stinger missiles, ontop of the Bradley sat in spawn. So the moment you take off, you got countless barrages of lock on missiles heading your way.
I get you don't want air vehicles dominating infantry, but you also don't want air support being literally useless. There needs to be balance.