Replacement is the only theory that makes 100% sense.
He wants to flood the country with non-traditional people because it will change the voting dynamics though demographics change.
The goal is political power, just like how the Bolsheviks carried out a genocide against the Kulaks in the late 20s-30s.
He is the ultimate Benedict Arnold and won’t even be labeled a traitor by anyone but the right, and not all of them.