Anti-Whiteness is the real reason.
What is the continuing, and increasing, breakdown of civility, and fomenting of political violence, by the Left really about?
To understand this properly, one must clearly distinguish perception from reality. As regards reality, at best Trump is a well-meaning vulgar ignorant buffoon; at worst, he is a “New York values” left-of-center fraud posing as a right-wing populist in order to fool the rubes. Considering that Trump’s Attorney General is the radical SJW Antifa Jeff Sessions, the latter possibility is more probable.
But, in society and in politics, perceptions matter. The perception – based on Trump’s cheap rhetoric and based on the sort of people who voted for him (and why) – is that Trump is some sort of “racist, fascist” right-wing populist demagogue, who channels White fears and resentments. In addition, instead of seeing Sessions as their legal man in government (which he is), the hysterical Left views Antifa Jeff as some sort of warmed-over Gestapo chief. The fact that these perceptions are ludicrously at odds with reality does not matter: a significant fraction of the American populace believes it and the mass media promotes it.
Thus, based on these perceptions, I have argued that hatred of Trump (and his staff) is a proxy for hatred for Whites; thus, all the sweaty, hateful fetishes and fantasies these people (including White leftists) harbor toward Whites comes out in their unhinged demented fury at the leftist Trump and his SJW staff. Perceptions, it is all perceptions.
Therefore, given the genocidal animus these folks have for Whites, is it no wonder they pose with mockups of a decapitated Trump head or say “Fuck Trump” at a media-covered celebrity event or shoot up a GOP congressional baseball practice or attack Trump supporters (with Sessions providing legal cover) or harass Trump staff wherever and whenever they show themselves in public?
You see, to these people, including Homo erectus Maxine, Whites have been getting too uppity recently. They are not quietly and humbly accepting the steady march toward White dispossession. The perception of Trump has thrown a monkey (no pun intended) wrench into the multicultural apparatus and the Guks and their White traitor allies are enraged at the temerity of these Whites. Why doesn’t the lowly White Man know his place? Sit down and shut up, Whitey!
That explains much I think.