Steve - really, it's fine. I understand Keven very well, and quite honestly, nothing he said was rude, crude, mean or the like. He was just expressing an opinion based on what the thought he had read. Just a misinterpretation on his part, just like you and I had a misunderstanding based on what you thought you were reading. Like I said, when he is wrong, he apologizes, as you do, too.
Keven - I don't know if self-certainty is the word I would use. I think "authoritative" is a better description! I think we're all pretty certain about our opinions. You're passionate about what you feel, but sometimes you just have to chill out and give folks a chance to express themselves without them feeling that you're going to just trample over their feelings and opinions...which you sometimes do. It's probably unintentional, but still, can be off-putting and have a "stir the shit" effect on a group. As a teacher, you of all people know that you have to allow folks to think for themselves, and form their own views and opinions, not plant them in their heads for them.