What motivates the often unreasonable words and actions of local and national leftists (not liberals or average Democrats)?
Assuming good intentions, maybe the dedicated leftists now controlling the Democratic Party are convinced they're good, moral people pursuing the noble end of human paradise on earth.
That understood, anyone agreeing with them in how to pursue that noble end must also be good and moral, and anyone disagreeing must be stupid, evil and immoral and must therefore be crushed.
In the leftist war of good against evil, any weapon is justified, including lies, character assassination, hate, even violence. After all, the evil opponents are by definition liars, character assassins, haters, prone to violence. Fire must be fought with fire.
If there isn't evidence of opponents' evil nature, it's because they mask it. Any initiative by them, however seemingly reasonable, is just a weapon in their war of evil against good.
Not so. All members of all groups in our improvable but imperfect world are flawed mixtures of good and bad.
We each must work to improve the ratio of good to bad within ourselves, but we can't see into the hearts of others. We can't really unreservedly praise or damn them or assume their intentions without objectively provable evidence of consistent good or evil behavior.
A truly absolute evil is "knowing" we are good and right, while those disagreeing are evil and wrong, thus justifying our own evil, hateful actions: lies, character assassination, violence, etc.