I don't know about you, but if said 'mob boss type figure' threatened everyone you know, to the point of making it clear that she'll ruin your best friend/open relationship girlfriend's life so extremely that she'll end up in massive debt and be forced to drop out of Uni, and subsequently end up working a job where they need to test for STD's on the regular in order to do their work, I'd sure as hell do whatever I'm told to do as well. No amount of superhuman strength is going to solve that problem, no matter how you try and twist and turn the situation around in your head. There's a reason why super heroes wear masks, not because they can't protect themselves, but because they won't always be able to protect the people closest to them.
As for 'defending' herself, here's a sorta hard truth for you. The world doesn't know about succubi, so she can't really walk around blowing people's heads up with her strength just because, and that is the truth of what would happen. She's been lucky so far that the only people she's hulked out on are other succubi that can take that level of power. If she did however hulk out like that on humans where there's witnesses, that's a really good way to out your entire race to the world, and giving yourself an even bigger spotlight than you already have. Something MC hates by this point in the game.
As for the family and others blowing up at her and treating her poorly, I already responded to that in the last post where I said I agreed with the point you made on that front, it just wasn't important in your first post where you were obviously more upset about her not having a spine. Which for the story that's being told, and where we're at in the story by this point, makes total sense.