Yeah, I'm missing something here. Outsource when there's a big unemployment problem here in the US? TAs really aren't qualified to do this work? And they're being given to outsiders who have no knowledge of the class (i.e., "yeah, I can see why you said that because in class, Mary said...") and whose native language isn't English? This seems like a fail to me, what am I missing?!

What you're missing is that most universities (public ones, anyway) subsidize (i.e., flat-out pay for) the tuition of their TAs, in addition to paying them their pittance of a salary. It's much cheaper for the institutions to send the jobs overseas to people who speak nominally correct English. It's worse for the undergrads, and worse for the TAs (who, let's not forget are also students), but it's better for the university's bottom line.

(I sent this to my boss last week. As horrible as I think it is, I'm also in the position of hiring and managing our department's TAs, so there's something about it that's just a wee bit attractive.)