So long as we are not in a hot war with Marxists, I would take a different attitude. I would consider them as good people who sadly deeply miscomprehend how the world works, often because they aren't grown up yet, but many times because they never really used their mind, or they put up walls in their minds preventing them from entertaining any hypothesis that contradicts what they think they already believe.  Many people grow out of it.  You can't talk them out of it, but it you hold up a figurative mirror to them, eventually they get it.

Take Jimmy Dore. He's a funny guy, a well meaning guy, who still believes in socialism. Ok maybe he would be against these guys you are talking about, but he still supports socialism, Venezuela-style. Yet I'd also be happy to have a beer with him and argue about it.  I'm not ready to "deal with" him.

If however we are ever in a hot war with Marxists, then yes I would then call them "mindless fuckwits" and "pond scum" because I would need to work myself up enough to be able to shoot them. That would be a horrible thing.