Marxists is even better. I’d call em “commies” but they love to pretend communism died with the cold war, and then wriggle around by saying they are socialists, not communists. “Marxist” doesn’t give them any wiggle room.
Marxist works for me except there are more literal meanings and distinctions between socialism (the government distributes your money to certain chosen industries) and communism (the government RUNS the industries).
“Leftist” covers them all.