Originally Posted by LoganFlyer

I have no inside information, but I'm guessing it's because the international check-in area is part of terminal F. Keeping the international flights out of E & F makes people's trek shorter from the check in area to their gate, and checked bags have a shorter distance to travel as well. (Yes, I'm aware you can check in at the domestic side for an international flight, but I'm guessing fewer people do that.)