Dershowitz is a civil rights activist -- he is very anti-censorship (as long as you're not dishing on one of his clients) and has been one of the few on the left to criticize the fascist right-think that has overrun U.S. university campuses. He's also one of the top defense attorneys in the world and very, very, very good at protecting his clients. He uses the law like a laser-guided missile to intimidate, undermine and neutralize whoever is on the other side.

Why would a guy who was heavily invested into promoting pizzagate... be helping Alan Dershowitz and Jeffrey Epstein?

This is a very very good question that has not ever been sufficiently answered, though @RebelSkum dug into it pretty deeply at pizzagate.wiki. One reason might be to get Derschowitz to be part of his big documentary "Silenced" that just came out. Derschowitz is pretty impressive in it...much more than the lisping Thermobitch.