If we wish to understand what’s wrong with today’s politics, we ought to consider something F. A. Hayek pointed out long ago. It should have been obvious, but it escapes many people: namely, the more power government officials have over our lives, the more people will fear its falling into the “wrong” hands, that is, the hands of those who disagree with them. In response to a growing fear, they will be willing to undertake ever-more-extreme measures to wrest power from those hands or retain it for the “right” hands.
Who can deny this? Government is force. It is imposition — not merely on people who really abuse others, but also on perfectly innocent people who mind their own business. Since that is so and since few people like having things jammed down their throats, as government officials control more and more aspects of life, including and perhaps especially cultural matters (through schooling, for example), people realize they have two only choices: be a victim or be an aggressor. Many people will choose the latter and be willing to go to great lengths, even street violence, to protect themselves and their families. (Note well: This is not an excuse for violence.)
If you wonder why zero-sum politics has become so acrimonious, therein lies a clue. (Other factors may explain the timing, etc.) You want less acrimonious politics? Strive for less politics. And that means replacing government with freedom, consent, and markets. We really have no other choice.