Good point, if it's part of the game's background I won't argue.
But considering the cost of MRAPs and their rather large size, I would think that there would atleast be some form of special forces vehicle that was designed in a lightly armored, low profile fashion.
To add to that, I would find it hard to believe that the AAF would be able to afford or maintenance an arsenal of MRAPs. I think it would make sense to see an American Humvee (or some other old NATO vehicle) in the AAF, as they already use hand-me-down uniforms, vehicles and weapons. Considering that the US has 150k~ of these vehicles, of which all have been ruled out of service by the Hunter in 2030, some would surely find their way into the AAF.