The result is that significant numbers of people now see themselves as the true Americans defending democracy from king Hitler Trump, and saving the nation from his far-right Nazi MAGA cult followers. They see themselves as little Schindlers protecting the neo-jewlike illegal immigrants that the ICE Gestapo wants to round up and make disappear. They see those on the Right as evil authoritarian Fascists who want to re-establish slavery, eliminate women's rights, and impose a Christian authoritarian theocracy that would persecute gays and trans and furrys and anyone they could label a deviant.
They are so convinced of their righteousness and of the evil of the right, that any action, up to and including murder, is justified in the struggle against what they see as manifest evil. If it was right to kill Nazis before, it must be right to kill Nazis now. Their virtue knows no bounds, the evil of the perceived Fascism they struggle against knows no limits—at least in their minds.
With that mindset, it is only natural that they would cheer the death of a leading conservative figure, that they would seek to protect illegal immigrants from removal, that they would advocate and practice violence against law enforcement, and loudly protest any attempt to enforce laws. The question becomes, how did we get here?
Perhaps the most obvious source is our education system. Hijacked by the Left, our once superior education system has degraded to the point where nearly half of the students cannot read at grade level, and fewer still can do basic math. From the perspective of the needs of our technological society, our education system is a massive failure. From the perspective of the Left, however, it is a resounding success.