I never discuss politics, sports, or religion in any place of business unless it is 100% safe. I'm thinking about the guy next to me not myself. But I've been to places of business where the owner is very political or religious and I've found that his/her rants affect business negatively regardless of party affiliation.
Why piss off half or more of your potential customers/fellow office workers? It's not worth it and Sean/Rush/whomever will not see a penny loss from their wallets while you're looking for a new job, or wondering why you're not promoted.
JMO.
He was not discussing the show or listening to it loudly. He had it on his headphones!