Angry not 'special' people, just not everyone. I have a lot of friends who are women and are not trans (cis women is technically how we describe ourselves but you don't approve of that term on the boards).
Some of my friends would absolutely feel oppressed by a dress code forcing them to wear skirts/dresses or heels. They'd probably be incredibly uncomfortable and even feel anxious or depressed because of it. Some wouldn't really care either way. Some would choose to follow the dress-code even without the dress-code in place, so for them it's not an oppressive thing.
I don't think something can oppress you, if you don't feel oppressed by it, but obviously it can oppress other people.
Living in the UK, I'd back any collective campaign to stop sexist dress-codes, or anything else that helped dismantle oppression.
If I lived in the US I'd be reluctant to put my job in jeopardy unless it was becoming impossible for me personally to work under those conditions. There just aren't enough safeguards there to protect workers, and there isn't enough social security to enable people to live without a job.