I have no idea if this person actually has antisocial personality disorder, but there is a misunderstanding of what the disorder is on this thread.

And I feel like a sociopath wouldn't waste time doing an AMA,

People with antisocial personality disorder (i.e. sociopaths) lack empathy for other people, but that doesn't mean they lack curiosity about other people. Lack of empathy means the person is incapable of "putting themselves in another person's shoes". A person with ASPD might struggle to understand why someone is crying after seeing their dog hit by a car, for instance. They don't understand other's emotions. But, that doesn't mean they don't desire to understand or that they aren't curious, in general.

because AMA's are for people who care about others

It's surprising to me that you think this because I've always considered it, more often than not, to be about the person doing the AMA. It's their interests, they're answering questions about themselves, the whole show is about the person doing the AMA. I would think sociopaths would be drawn to AMAs more than the average person.

as in seeking attention and conversation with others.

The average person with ASPD would be all over it.

as in seeking attention and conversation with others.

People with ASPD are absolutely capable of attention-seeking behavior and conversations with others. It just occurred to me where some of the confusion has come in . . .

The term "antisocial" in this context doesn't mean the person doesn't like to be around people or has no interest in being around people. In fact, some psychologists want the name changed precisely because it's confusing to the public.

Antisocial here means, basically, "incapable of having meaningful, mutually empathetic long term relationships". In fact, there is a whole segment of the ASPD population who are especially outgoing and popular among peers. These people are often highly successful specifically because they lack empathy, but are great at feigning it and/or charming (e.g. the charismatic cult leader, the Wall Street big wig, the suave serial killer). Typically, these individuals are capable of maintaining superficial relationships, but struggle with longer term, meaningful relationships. Sometimes they are very good at hiding their lack of empathy (survival method).

Source: Behaviorist; Supervised a behavioral health program, which included individuals with various challenges, including those with high functioning ASPD diagnoses.