I have the impression from what I've read about psychopathy that the category itself is a bit of a mess. The checklist of behaviors reminds me a lot of chronic pain diagnosis of what is most often called "fibromyalgia" these days. The same symptoms of pain and fatigue can result from a hormonal imbalance, auto-immune issues, sleep disorders, vascular problems, low grade infections, suppressed emotional trauma, etc. the root causes that exhibit the same symptoms can be completely unrelated.
If you look at any other neuro-atypical issue, these are not connected to sadism. On the one hand it seems like it's being diagnosed based on external symptoms which could have diverse root causes, but on the other hand there is this specific issue of amygdala damage that is being suggested to have neutral outcomes for non rage based psychopaths. Is the definition looking at a single root cause that can exhibit in a variety of ways, or is it looking at similar external manifestations without examining root causes?
I don't know of any other neuro-atypical issue connected to a particular form of sadism. Aspbergers and other high functioning autisms have hyper focus, some extreme personal hypersensitivity to emotional and sensory data, can at times lack empathy, and yet there is no particular connection to being cruel per say, although there are likely people with Aspbergers who are. Do you see the inherent confusion I am seeing in this topic?
I find this lack of clarity makes this issues a mess to parse apart and discuss. If there is more clarity available, I'd be especially interested to see it. It would change how one would best approach this topic.