I think parades are always a bit over the top, whatever group sets them up. Benji's reference to Mardi Gras is quite apt, since to me such an event finds its roots into the old carnivals, those old (medieval?) events in which role reversal is enacted, and pretty much everything goes. The thing is that nowadays, putting up bits and pieces on film/ video doesn't quite do justice to the spirit of any festive event, in which participants are free to "let it go" for a while.
With a properly edited video of the bars street in my city at closing time, I could start a campaign against drinking, for the behavior of some of the patrons is pathetic to say the least. Nevertheless, I think allowing outlets for excess is a need for a healthy society. Making sure this will yield minimum side-effects is the responsibility of the organizers of such events, but I don't want to live in 19th century Denmark (thinking of Babette's Feast, not meaning to hurt our Danish friends...)