Well, no, it isn't. People choose to go there. Don't make excuses for them.
No, it isn't exactly inevitable. I intended the "somewhat" to show I understand it's a choice. My point was that over time we're somewhat bound to come across it...particularly online.
Given that, it just seems like a shame for a conversation that's being enjoyed to stall because something someone else said that happened to be disagreeable. If someone finds the topic interesting and it is inspiring thought, I really want to hear about it.