There appears to be a subtext, from the posts so far, that the USAF crews were clowns and should have known better.
I will stick my hand up as a fellow FJ aviator and say it looks like an honest mistake in what really is very cluttered airspace.
They were under IFR and receiving a service so, despite local knowledge, I think they can be excused for the error. I think ATC, despite mitigating circumstances, are equally culpable.
We don’t always have to jumpy on Johnny Foreigner and make out we are so much better than them. Besides, have any British crews ever gone overseas and made mistakes due to inadequate local knowledge?
I suggest this Airprox is a timely wake up call and not really a major story. No harm, no foul.
BV