On one hand, I can see it being insulting, from the standpoint that these guys are being asked to do something that is potentially embarrassing to them, even though it's more than likely just a light-hearted thing. After all, it reinforces the notion (on some level) that these guys are dressing in a way that they are not "supposed to," or that dressing as a woman is something that just ought to be laughed at.
However, I don't think it's really the intention of people who organize these things to mock CD'ers or trans people, by any means. I think a big part of it is just that guys who are through and through masculine do look funny when they're not dressed in a cis fashion. I mean, a guy I know dressed as a Hooters girl a few Halloweens ago, and it was pretty amusing to see. I didn't find that a bit offensive.
I guess you just have to take the whole context of the thing into perspective. Are the women going to be dressing like men also? Will the guys just get glammed up so everyone can have a chuckle at seeing the QB in a dress, and then everybody forgets about it and moves on? Or will it have a more sinister undertone? That's how I'd judge it.
You certainly wouldn't be wrong for being offended, but I just don't see it as a huge deal as described, personally.
