Again, that was a decision (I'm almost positive) of the original poster, who I think was afraid that the thread was about to get out of hand.
The problem, IMHO, with discussions about politics, religion, guns, etc. is that people's thoughts tend to be deeply embedded in them and not really up for change. If we're talking about decoction mashing, for example, and I'm Dude and I think it's a complete waste of time, I'm still apt to read the discussion, maybe learn something about it, and MAYBE my opinion will change. Whether I love decoction mashing or I hate it, it's not something that's a core fabric of my beliefs and how I view the world.
Religion; I'm not a religious guy, I would consider myself agnostic; you could talk to me about why you're a Christian all day, and it's not likely going to change my beliefs (err... lack thereof). Politics; I'm a left-leaning libertarean who loves fiscal responsibility and a live-and-let-live approach to social issues; nothing you can say is going to make me into a hardcore Republican. Part of it is how I was raised, part of it is thinking and philosophies that I have developed and integrated into myself for years and years.
So, those discussions... you're not going to get any converts, and when people talk about them in a way that conflicts sharply with your own personal beliefs, well... that's when it gets personal. They feel like attacks on something that's very much a facet of who you ARE, and you tend to react strongly and negatively.
So - let's talk beer, people!