It’s always the extremists of any persuasion that cause the problems. The more people moderate and learn to respect and perhaps even learn from others who happen to not think exactly the same way about something, the better off we will all be.
I think narcissism or perhaps just mere selfishness tends to be the driving force. If you care about others, you will respect them and value their opinions. If they act like a yahoo, then all all bets are off. Everyone just be civil! IS that too much to ask? Apparently so. As was pointed out above, conflict is a natural thing that is a part of Homo Sapiens as well as most every other species on the earth that battles for survival. But Homo Sapiens have the ability to learn and maybe evolve? Or maybe not so much. The jury is still out apparently.