A simple body count (and in good liberal fashion, I'm going to make you look it up yourself. It's not my job to educate you) shows that Communism is at least five times as bad as its poor cousin, National Socialism.
If we fought a war to utterly exterminate Nazism, and we did, and it was moral and just, we should absolutely be doing the same thing for Communism. We should kill every single one of them for the good of humanity. No one is forced to be a Communist. It's not a race, a gene, an orientation. It is strictly a choice. If you choose to put the body politic so far over the individual that the individual becomes a tool, you deserve to be killed.
I've even had one justify to me that "99% of people won't do the right thing unless they're FORCED to." (Emphasis theirs.)
They were correct, but not the way they meant. Communists won't do the right thing unless you force them, by killing them.
Now, if you just said to yourself, "But Stalin and Mao and Pot and Kim weren't real Communists," and unspoken, you're avoiding mentioning Castro and Chavez, and don't even have a clue who Haitham is, then this is the response:

If your attempts at "real communism" consistently, 100%, decay into "not real Communism" that has killed well over 100 million people in a century, then you need to be killed, too, because you're vector for the virus of Communism. You're either incurably insane or evil, and you need to be dead.
It is the triumph of Western democracy that philosophies are allowed to exist and propagate even if they are ultimate evil. It is the failure of Western democracy that we support this to a fault, of allowing Communists to breathe air needed by human beings.

Then we can get back to killing National Socialists and regular Socialists as well, since their difference is only one of path, not destination.