Throughout the election the Left and the media have accused Trump of being "Hitler" and his supporters of being "Nazis". They claimed that the only way to defeat such "hate" is with "love". As such, they created the slogan of Love Trumps Hate. The slogan implied that Trump is Hate, and the Left is Love.
Once the Left lost the election, the pic below was an example of their "Love".
The Left also conducted "thought experiments" last year concerning if it would be morally ethical for a time traveler to kill baby Hitler. Of course, the moral answer is NO, it is not OK to murder an infant. But they even got idiots like Jeb Bush to claim that such an action would be ethical.
So we have now established that it is fine to kill people who we claim are "Hitler" and "Nazis." Of course, the Left has a long list of people who are "literally Hitler" such as President Trump. And anyone that voted for President Trump must logically be a "Nazi".
You see this logic with tweets such as the following:
Guterman is implying that maybe somehow history got screwed up by a time traveler who prevented someone from killing Trump (aka "Hitler"). The implication is that the world would be in a better place if Trump was assassinated. And this guy is a "mental health" expert.
Guterman may never personally throw a brick at a Trump supporter. But he provides the moral justification.