I don't completely change my views, but I do fluctuate in how passionately I defend my own view and argue against another's.
I also tend to sympathize with the underdog. If I feel a person is being attacked for little to no reason, even if their views are the polar opposite of my own, I will state my opinion in a calmer, more respectful manner than I might under other circumstances. If someone from my own "camp" is being extremely militaristic or judgmental, I will argue against their attitude and the way they are trying to spread/display their views, but not necessarily against the views themselves. I wouldn't say that I argue both sides, just that I have the ability to sympathize with both sides. After all, I've BEEN on both sides.