I've been to GayDay every year for the last seven years, and I was only embarrassed by our behavior one time. This was three or four years ago, and it seemed like a vocal group of idiots (not a large group, but a very LOUD group) were just out of control.
Basically, they just pretended they were the only ones in the park, and behaved that way. Obnoxious, rude and vulgar just begin to cover it. I told myself that was the last time I was going to go to GayDay and be embarrassed like that.
Fortunately, what came out of that was a major emphasis on behavior, and how people come into a situation like that with pre-concieved ideas about gay people, and acting like a bunch of out-of-control jacka.s.s.es only reinforces those ideas.
I've been every year since, and have thoroughly enjoyed myself. The lesson seems to have been learned. If you decide to go, just keep in mind that Saturday, June 7th, is THE big day, and the Magic Kingdom is usually full to capacity. The rest of the'official' days are more of a suggestion than anything else, and the crowds aren't noticeably bigger.
Hope this helps!