Here are some other ideas for you, Dan:
Dad costumes
If you want to one-up this guy, make sure your moobs are pressed together and lifted and put on display.
Oh, okay, yeah, I see what you're saying, that's the sort of thing that Mighty Girl points out and tries to raise awareness about.
I also don't see the problem. If either of my daughters (or sons) wanted to wear that, I wouldn't have a problem with it. It's just a darth vader costume with a skirt and knee socks. It's not particularly "slutty" or revealing. It's campy fun. There's no need to get uptight about everything.
Actually, that'd be a great way to harrass my kids, I wonder if they make one in men's XXL...