According to Volokh's blog, it is illegal in California to make a private racist comment to a roommate. He says:

On May 7, the California Fair Employment & Housing Commission penalized Melissa DeSantis $500 for inflicting "emotional distress" on a would-be roommate by allegedly telling him that "I don't really like black guys. I try to be fair and all, but they scare me." It also required her to pay him $240 in expenses -- and take "four hours of training on housing discrimination."

I agree with Volokh that this is contrary to basic rights to free speech and freedom of association.