In this particular case it is. You can’t wear political clothing in a polling place. This law applies to everyone. To indignantly take your shirt off is disrespectful to the people there. It would be the same if it were a man taking his shirt off.
The fact you instantly made it into some sort of anti-feminist or sexist screed sounds paranoid. Are we really this suspicious of each other?
Do you honestly think “no shirt, no shoes, no service” makes for a worse society?