I don't think anyone's really got the moral high ground when it comes to this stuff.
If your point is that every group of thousands of fans has drunken idiots who spew hateful stuff, I agree with you. (Equally, there are wonderful fans with every club as well.)
If your point, however, is that every club's fan culture is the same overall and equally tolerates or supports this stuff, I reject that. This is more than a few fans on a subway with Chelsea.
Yeah, claiming Chelsea has just another fan base is like claiming Millwall has just another fan base.
Chelsea had some well known violence issues back 30-40 years ago. The past 15 years the club has regularly featured African and other black player whose names we all know including four of the most prominent Africans ever in Weah, Drogba, Essien and Etoo. There are songs and banners for Drogba, Essien, Cole, maka, Kalou, Mikel just to name a few. The club featured I believe one of the first ever foreign managers in English football, the first ever all-foreign lineup in England in the late 90s and I believe one of the first black managers in England. It has a very prominent Jewish owner, a superstar west African president, a long line of foreign managers and is run by a woman. Does that describe Millwall or ony other club in England today?