If the FBI is involved (interfering with a crew member's duties is a federal crime), they can add her to the no fly list via TSA if warranted. And I think all of these people that act up should be, or in the case of psychiatric reasons, should be required to fly with a caretaker.
I am not sure why my other comment was downvoted to oblivion. ONE airline banning a passenger is NOT the same as being added to the no fly list. Period.
Injustice anywhere is a threat to justice everywhere.
Barring them from all possible flights for the rest of their life, which may yet last many decades, is likely to do more harm than good because it will cause resentment that can block this improvement in a person. By contrast, barring them from just one airline allows them to continue to live their life while also acting as a permanent reminder to be better.
In case it isn't obvious: the number of people who can be triggered to be violent in the right circumstances is far higher than the number of people who have been so triggered. It's probably a significantly double-digit percentage of the population.
If we wanted such private bans to be rehabilitative then private companies should not be allowed to impose life-time bans.