Well the way I see this issue is that it centers not around the series (so don't be embarrassed) but rather the maturity of con-goers.
Con-goers tend to be a younger crowd or even some older people just don't know when to go grow up. I was actually a victim of a display of immaturity (though on a smaller scale) at last year's Anime Boston.
The series has attracted a large younger fanbase, and being teenagers, you do stupid things. I always feel iffy when hanging out with other cosplayers. I worry about if they can display the certain level of maturity to not annoy me.
Well at least one of them feels sorry about it. I think its alright to cut that one some slack because everyone is probably jumpin on him/her right now. The rest though, needs to realize how idiotic and insensitive they were acting.