Youre all over the place here. So I'll reply the best I can. She sabotaged them because they were prisoners with the intention of being used as pawns. Like you said to protect american involvement, but then you mention in your last post and this one; that she is only in all of this for herself. If the invasion makes it's way toward american soil, that indirectly messes with her, and her narrative. So why would t she do something?
Of course there are other heroes in this universe, im not sure why this was brought up either, but where were they when the giant monster was fukking things up in Mexico, see that's irrelevant to the story line at hand.