As many of you know, Bob Prokop and I go back a long ways, to our days as ASU undergraduates in the mid-seventies. We were members of a science fiction club called OSFFA, the Organized Science Fiction Fans of Arizona. Bob and our late friend Joe Sheffer were the resident Catholics, I was the token Methodist, and the President, as I recall, was an atheist and Heinlein fan named Bill Patterson. There were a lot of very passionate discussions. I don't think we ever were paragons of disputational civility. In fact, at one of the discussions was cartooned by an artistic member, showing Bill with a T-shirt that said "Heinlein is Power," Bob with one that said "I agree with nothing!" and Joe with one that said "I am wise." (I wasn't there that night).
Alas, Joe passed away in 1989, and Bill passed away a couple of years ago. He was known as the official biographer for Heinlein. And, to my knowledge, he remained an atheist throughout his life. But he ended up being heavily influence by St. Thomas Aquinas, and described himself at one point as a Thomistic atheist. He also was an opponent of abortion.
It isn't just niceness that makes productive discussion possible. But there is a state of mind that really tunes out people on the other side.