No. It's how they behave around me that matters. I could care less about someones politics if they are a decent person.
I normally try not to let politics color my perception of people.
Of course, when they are blathering loud mouth idiots about it, I have a hard time enjoying their company. The same can be said about any fanatic type of person, whether they are fanatical about politics, religion, diet, exercise, whatever.
As far as 'famous people' I could care less. Less than half of what you read, good or bad, is actually true anyways.
As far as personal friends, I'm agree with Mark. As long as they are not total asshats when I am around it really does not matter. I have friends that are politically and socially both to the left of me and to the right of me (politically speaking).
+1 To the above - be a decent person, and don't yammer away/shove your beliefs in my face if I don't want to hear them, and I'm fine with you. Unfortunately, we've all encountered people either personally, or through the media, who don't seem to want to follow this rule. My brother tried playing "Jr. Preacher" at family gatherings some years back, to the annoyance of everybody else (he felt we "all needed saving"). It got so bad, that my dad finally had to read him the riot act, stating that either him and my sister-in-law cool it with the preaching, or they wouldn't be welcome at family get-togethers anymore. He did cut it out, but still occasionally seems to feel the need to "instruct" everybody in the family of the "error of their ways." Unfortunately, since he's my brother, I have to put up with it to an extant (although there have been cases, where I've just walked away from him, when he's started to exhibit that kind of behavior).
My friend (who lives out of state), calls me on Fridays to keep in touch (since I'm on vacation today, I'm debating calling her this afternoon, rather than having her call me tonight, keeping me on the phone until who knows when). She's a decent person, but a conspiracy nut (she listens to Alex Jones daily online, and thinks he's the greatest), and also thinks Ron Paul is the bomb. Oh yeah, and she gets kind of New Age at times. As a result of these three things, I usually have keep an eye on keeping the phone conversations from veering off into politically oriented, or health related topics, since they have a tendency to veer off into never-never land, when I talk to her. Otherwise I get annoyed, and occasionally angry - especially when my friend responds to my annoyed responses, by saying that she's just trying to "remove the blinders from my eyes", which has occasionally in the past, resulted in me hanging up the phone on her.
As for celebs - well we have no control over their outbursts, and since most of the time, IMO, they don't have any expertise, in the topic they are spouting off about, I just ignore them.