With Rush Limbaugh's sponsors and radio stations dropping like flies, it reminds me, I had a similar situation about eight years ago.
While living in Las Vegas, I hosted a show on a brokered time radio station. With this, I was responsible for garnering my own sponsors. My show was attached to a web forum, in which listeners could post commentary on various show topics. One of the contributors to this forum posted some very derogatory remarks toward a young lady that worked at the company in which my show was focused on. My primary sponsor let me know they did not want to be associated with such vile remarks made about this person. As someone who believed in free speech, I felt it was my choice to keep the posting up. The sponsor told me that if I wanted them to continue our relationship, I would have to take the posting in question off the forum, and the issue an on air apology. It taught me a valuable lesson about free speech. When somebody else is paying the bills that allows you to speak, the speech is no longer free.