Haha nah there's nothing wrong with liking Green Day. Their first few albums are really good and they really connected with the sort of aimless feeling in young people in America at the time. It's kind of a meme to rag on them in punk circles because they got mainstream popularity and an image of being this mad subversive band with some of the most milquetoast, myopic anti-war music ever and if there's one thing punks love it's saying things aren't real punk.