I'm pretty sure cosplayers anywhere in the world don't wear their outfits to or from the events. Those things take a lot of work and and I would feel so sick if something happened to it because I wore it to the event instead of putting it on in the hotel room.
As for the "they dont have the right to tell me what to wear" silliness they can just not let you into the event too. Some rules are there for your protection. Think about the police here in 'Murica. They like to shoot first and then claim they felt threatened later. What if you were cosplaying a character with a weapon?
Not sitting down inside the event area and reading your yuri? Have you ever seen the crowds outside of Comiket? If you have, it's worse inside because it's enclosed.
Photoshoots in the event area would cause congestion and someone could get hurt.
Not camping outside of the event area so you get closer spot in line, there are a crazy amount of creepers and perverts in japan, not to mention other dangers that want to prey on women.
Those rules/requests are not there to infringe on your rights, they are there for safety and also for the consideration of others. There's a time and a place for squealing about your rights being trampled upon, an event like this isn't one of them; and especially not if you're a westerner, you'll just make the rest of us look bad.
