Here’s a long discussion in a Usenet group devoted to bicycling that begins when a veteran, reasonable, commenter announces that he is leaving the group because he is tired of the vicious personal attacks and speech-suppression attempts that increasingly accompany discussions of technical topics as well as anything that veers toward politics. The commenter singles out another contributor for having driven him to decide, finally, to stop commenting.
A few posts later, the accused individual responds with: “All you have to do is not talk about politics and I wont bring up your more disgusting political views.” Which kind of proves the first commenter’s point.
I didn’t come into the discussion until somewhere around the 300th post, where some guys are arguing that religion in general has killed more people than secular totalitarianism, and that all religions are equally responsible for genocide and terrorism. The few people who point out that Stalin, Mao et al weren’t religious, and that maybe Islam is a bit more of a problem today than are Christianity and Buddhism, are dismissed and sometimes insulted by the others. This discussion has almost 500 posts by now.
Some of the people who contribute to this discussion and other discussions in this newsgroup are very knowledgeable about bicycle technology. However, on other topics, particularly politics, they tend to be tiresome cranks. Some of them appear to be crazy. And without moderators to prune out the abuse, the cranks quickly drive off the reasonable commenters.
I think this is just the way it is on the Internet, and that anybody who wants to create a productive discussion environment must be ready to spend a lot of time and effort moderating discussions.