DISCLAIMER: I post this as food for thought, not to take it as fact. It’s only one person who said this, and this psychologist also did not seem to differentiate between primary and secondary psychopaths, which I’d consider a pretty strong red flag.

A clinical psychologist touched a bit on this in this, I think in this video.
Basically claiming that at the core of psychopathy there is (somewhat paradoxically) fear. They learned that genuine connection, love, etc. doesn’t work to provide safety (or, considering the science of primary psychopaths, that they are genetically tuned that way). So the alternative, or one of them is controlling people. Similarly, sadism can be seen as the pain in other people that are validation of one’s control and therefore safety.

Of course this often completely backfires, because pushing people far enough can make them more unpredictable too, etc. Not to mention how utterly destructive it is.