Well, part of this is the 'sacred cow' thing. Like it or not, everyone has certain things that are non-arguable to them. It might be politics, religion, environmental, immigration, whatever; and as soon as that comes up, they get very aggressively defensive. Probelm is, most of the time, you dont really mean to insult their sacred cow, but once you do, it's on. In our normal life, most of us probably live, work, speak, with people of the same race/nationality/politics/world perspective/religion. Online, that's not the case. We probably have a New Zealand weed farmer, a militant environmental person, a Baptist preacher, and a city councilman, all on the same thread.