There is nothing uniquely American about extreme aggression towards people holding differing views. Although the current state of American society isn't great it can get so so much worse. A couple of examples.
1) The Cultural Revolution (China) https://en.wikipedia.org/wiki/Cultural_Revolution
Several hundred thousand to maybe a few million people were killed, often at the hands of angry mobs, for not being the right kind of communist, for not being communist enough or for just not being friends with the right people. A person could be accused by someone who didn't like them with zero evidence of any wrongdoing and still the victim would lose their home, all of the belongings and potentially their life. This lasted from the mid 60 until the mid 70s.
2) Something current https://en.wikipedia.org/wiki/Religion_in_Saudi_Arabia
Religious minorities do not have the right to practice their religion. Non-Muslim propagation is banned, and conversion from Islam to another religion is punishable by death