I don't think sociopathic is an accurate characterization. Carmack's behavior struck me as similar to someone with Asperger's Syndrome (based on the Masters of DOOM book.)
I've not read Masters of Doom, but I have heard Carmack describe his school-age self as a huge jerk. However, for a least the past 15 years he seems to have pulled a Gates (before Gates did) and has come across as one of the most genuine, nice people in tech. Not just in big, public displays but in every little thing he does in the constant public interaction that he has.
I see so and so's razor thrown around so often I think many should remember philosophical niceties aren't always true. Sometimes the simplest explanation is not the correct one and sometimes things that could be simply attributed to stupidity are malicious (and targeted because of the nice disguise).
I know a lot of people in the STEM field that simply find it easier to act like they're socially inept and treat people like shit rather than "put in the work" to have nice, courteous relationships with people. I'd argue some even feel it makes them seem more intelligent to "not fit in with the normies."
That's not to say Carmack is or isn't a sociopath. I haven't read much on him outside of acknowledgement chapters in game design tutorials. It's just really tiring seeing people dismiss claims with aphorisms like the Greeks got everything right and we don't have to reason anymore...