I dunno, really, I can enjoy a Green Day song, even an American Idiot one (if I'm in a good mood), but, idk, there's something about it that, is kind of phony. I don't hate Green Day, but I don't like them.
I used to be in love with them when American Idiot came out though. But I was what, 10? It might be an outgrowing thing too. I gave up Sum 41 recently too. Kinda childish.
I love the stuff from Dookie and before though. 1000 Hours is easily my favorite song my them.
I think a lot of people who rip on them have a personal bias.