She got sucked in for the same reasons other women get sucked into abusive relationships. Are we all stupid, too?
The point is that it's not about stupidity or how successful you are professionally; some abusive men (and that is what this one was) get a kick out of being able to control and bring down women in "successful" careers.
They go looking for somebody vulnerable, who doesn't have the boundaries to protect themselves, whose understanding of what makes a healthy relationship is not there, who is trusting or sheltered or naive, whose background will make them easier to manipulate.
Our culture and socialisation helps. The idea that it's romantic to be stalked and pursued, the idea that women say no when they mean yes, the idea that men are controlling because they care about you, the idea that you need someone to sweep you off your feet so fast you don't have time to be objective, the idea that a man murders a woman because he loves her so much...
Given her background I struggle to comprehend why it's so difficult for posters here to see how she ended up with no idea of what a healthy relationship was - basically looking at abusive ones and seeing love. It's pretty bloody obvious it would be difficult for anybody in those circumstances to have a good understanding of what a healthy relationship looks like.
Take issue with our toxic culture and the men who abuse. That is where your criticism and judgement should be directed, otherwise you are just as bad and enabling them.