No I'm telling you it's something people do because the danger has been removed.

That's what happens in the movie, Dorothy kills the witch. There has been a long long time since it was illegal to be gay, and the people that actually had to deal with that law are generally not the ones on the parade. So they certainly not celebrating the danger is gone for the majority of people who do parades didn't have that danger upon them.

I think this explains it:

http://richyrocks.com/coolenglish/wp-content/uploads/2015/04/simpsons-gay-pride-parade.m4v?_=1

Think about it how long this has been out.