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 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...