They're too fuckin dumb to understand nuanced material critique, so all you're doing is giving them ammo to justify their own anticommunist biases from a left lens. There is no nuance in mainstream politics and the discussions therein, only extremes of black and white, with freedom countries on one and evil dictatorships on the other. Stop it.
Anti-war messaging has anti-imperial effects, but doesn't require you to dive into conversations most libs aren't ready for. Besides, there's a pathway from general anti-war sentiment to more specific anti-imperialism (and even stuff like critical support for AES states).