Vindictive former FC leader manipulated her way back to kick all active members

[Alistaire]

was voted out of her position back when 3.3 hit for being inactive, abusing her power to demote/kick members who angered/disagreed with her

Since when has this been a thing in game? You guys sound like the ones in the wrong. If you don't like an fc leader's rules you're welcome to leave but nothing in game supports this kind of mutiny. If the game removed their status for # of days inactive that's fine, but you go on to make it sound like FC's are some kind of democracy, which they aren't. Anything you decide to do along the lines of "voting" carries no weight. Maybe your vote convinced her to step down and someone later told her that was bs (which it is).

I think this falls under section 3.2 of the FFIXV User agreement of prohibited activities of disrupting the experience of other players...

Again, they'd have grounds to report you for taking over their fc and disrupting their experience. Not the other way around. If they read this, they should really report you. And looks like they're getting a fresh start on their fc.

edit: even in the worst case scenario of them losing leadership due to absence and the way the game controls that, if they got back to fc leader they did it through the game rules which still means you have no case, and considering I found their name through 2 clicks because you named the fc you're breaking a 2nd big no-no here as well.