I wonder if it’s calling communists ‘commies’ that some may take offense to.
To my ear, this is sort of a slur in that I’ve only really ever heard it when some army guy is shouting ‘god damn commies’ or the like.
Just a disclaimer, I don’t have particularly strong feelings for either a communist or capatalist structure. I think shitty people tend to gather power so most of us are just taken advantage of in either scenario.