Yikes...
The argument can be made and isn't a fully unreasonable one that it is unsustainable for the USA to continue to rely on the courting of dual nationals. There's less of a focus on the pure domestic development of players when you depend on the recruitment of eligible players from other countries. That argument can be made.
Wambach's argument, on the other hand, doesn't seem to be that argument. Specifically, questioning their commitment to the team simply on the basis of dual nationality reeks to me. "Do they have that killer instinct? I don't know." is the worst one for me. There's something really infuriating about that to me, just in the way that it is so casually xenophobic.