I have. Several times. But then again, it's an area of fascination for me and I spend more time on them than most (I would guess).
For the most part, although many will say it, nobody is trying to change anyones minds. Most just try to articulate their position. Few do it well and it's often evident who has thought their positions though.
I wish people could discuss the topic without getting emotional, but they often do and progression heads south. I guess it's an emotional topic to begin with, and it doesn't take long for challenges to be taken as offensive, even if the goal is to better understand the issue.