. . . .and since it is third-hand we probably won't get any.
This is anywhere from a low-grade criminal assault, which should at least be reported to the airline by the aggrieved passenger if nothing else is going on, to a captain saying "Hey buddy would you please pull up the last few pictures so he or she the FA will calm down"? We don't even know what the FA was asserting happened--which would seem to have been really, really, really, really, relevant. (Although short of the FA believing something deliberately humiliating and possibly illegal (like upskirting) happened, I don't know how it could legitimize an on-ground "citizen's arrest"). But the crew do have personnel files. One off the wall action probably won't amount to much, and perhaps it should not beyond corrective counseling. But a repeated pattern of instability is of concern. Even to AA.
Assuming I will not be violating any Flyer Talk rules by posting the link, here is a five-year-old column from The Points Guy on taking photographs of other people in and around aviation:
What Can You Legally Film on Airplanes and in Airports? - The Points Guy
My summary of the column is you may have contractually waived your right to photograph. But nothing in a ticket agreement would seem to allow for random detention.