Because "true socialism" (like your true Scotsman) requires ideal übermenschen on all levels everywhere. This is not how the humankind works. Humankind is full of flawed, sometimes outright malicious people, and you have to deal with that.
Most versions of socialism at some point came up with a need to breed ideal happy socialist people that won't keep breaking their paradise all the time. And until this Übermensch is born, they chose to break and bend the rest into behaving, like bonsai trees. Of course, Dear Leader and their team is exempted from being broken or bent, and many others aspire to become like them. This is how every socialist rule to date grew into a totalitarian oligarchy.
Thank you but no thank you. I'd better choose a form of government that adapts to and deals with people as they are, and doesn't try to force them into some better version according to their understanding.