Trump divides individuals and nations into three groups: vassals, who do his bidding and accept his view of reality, at least in public, without question; strong adversaries, with whom you make deals; and weak adversaries, who get fed to the woodchipper. Zelensky failed the vassal test, so into the woodchipper he goes!
If it makes him feel any better, he was probably destined for the woodchipper in any event, because Putin, a strong adversary, will insist.