Hmmm now on this I'd normally say you can't blame a football club for the actions of its supporters but in the case of chelsea I'm not so sure.
They have a history, going back to the early 80s, of having a vociferous racist section of fans. Not the standard racists mind, politically motivated racists. Neo-nazi groupings in the 80s and early 90s like Combat 18, Blood and Honour etc all had leading members involved with Chelsea. They have affiliations with other teams with a right wing politically motivated fanbase such as Glasgow Rangers, and to a lesser degree loyalist paramiltary groups in ulster and white supremacist groups in south africa. There was a really good BBC doc years ago documenting all of this.
There's also a McIntyre doc about chelsea fans being racist in europe, but it's pretty lame. Notably only for McIntyre passing out while getting a chelsea tattoo on his arm. Twat.
Add to my little history lesson recent actions of the club with regards to racism. If I racially abused a colleague at work I would be dismissed. John Terry's backing and continued career at chelsea was pretty much chelsea saying "we don't give a flying fuck". And to be fair, they don't. They don't give a fuck about their fans. The real ones who have being going there for generations. And so, with that example, and atmosphere of being untouchable, what can we expect?