The fact that you believe this is the exact reasoning behind trying to prevent things like what Jimmy Kimmel did here.

It could not be more cut and dry than this. In fact it is so cut and dry that a conspiracy theory on both the left and the right is that the text messages demonstrating his political motivations aren’t genuine.

Are you asserting that he followed left wing influencers or read left wing books or attended left wing classes or somehow got his indoctrination from left wing sources?

There isn’t any evidence of that - there is only evidence that he hated the right wing (and to the contrary there is obvious evidence he came from a right wing milieu - just take a look at his parents). Simply hating a side doesn’t mean you have been indoctrinated by the other side - just look at people who left fundamentalist religious sects.