Because the single only way to do communism is how the UdSSR did it, there’s no other way.
It is, because one bad apple spoils the bunch if you don’t send them to gulags. Communism on a large scale is not self stabilizing unless everyone is ideologically 100% onboard.
It is. Education would not be sufficient for that unless you can program people with chips in their heads.
You then get a few people who produce something that is desirable and rare, start exchanging it for favors and you’re on your way to a systemic collapse.