Why state-owned enterprises are bad in a totalitarian empire? I mean comparing to what?

It does not need to be relative to anything to be “bad”.

A state-owned company in a totalitarian empire is part of a system that suppresses freedom of speech, uses forced labour, conducts genocide, seeks to undermine democracy overseas. That’s why it’s bad.

No. What you said has nothing to do with the state-owned enterprise. Is a piece of bread in your totalitarian empire bad? A state-owned enterprise provide employment, food and shelter for employees, and also provide social and economy functions for the general public.