Because women who don't wear bras clearly want to show their nipples to men and that makes men """uncomfortable""" but it's always the women's fault, they actually want to do that, it's the only possibility, and believe me, this logic is definitely not shockingly similar to oppressive behavior that stems from fascist/totalitarian ideologies coughs hard

And please don't use the argument that bra-less men aren't considered sluts, or else my unquestionably not fascist reasoning will be completely invalidated and I'll cry.