“Painting your nails is girly and therefore wrong” only works if we presuppose that being girly is lesser and wrong.
Not really. It’s also a challenge to the status quo, and people don’t like that in general. By that reasoning, cutting your hair short should’ve been seen as “manly, better and right”, but women who did that were initially frowned upon. Because it’s challenging the status quo, and privileged people who see no issue with the current society see that as a threat to it.