So an American walks into a McDonald's...

Recently, on the way back from a conference, J* stopped at the McDonald's in the Cambridge Motor Services. (J* is an American who has lived in the UK for going on 20 years now.)
British people will be the first to tell you that they "know how to queue" (line up). However at the McD's, there were four registers open and one queue for all of them that was beginning to stretch out into the main shopping area, blocking other people from getting by the McD's.
So J* figured the logical thing to do was begin a new queue at one of the open tills, which would more evenly distribute the people at each of the four registers. But as he moved to do so, he was accosted by a tall, lanky British guy about 30 years old or so, who got right in his face and said, "Now how's that fair?! What if one queue moves faster than another one?!?" When J* tried to explain that the queue was getting unruly, the British guy, noting J*'s accent, yelled, "If you don't like it, get the **** back on the boat to America!"
Dialogue from here:
J*: "I've been here for 20 years, sir."
Angry British guy; "Hey we had rationing in THIS country, so we know how to queue, alright! Here, why don't you just cut in front of me, would that make you happy? Eh?!?"
J*: "No, that's ok, I'm not really in that much of a hurry."
Now, several responses could have been made to Angry British guy, aside from the obvious two fingers.
1. You're 30. You weren't even *around* during the WW2 rationing.
2. Well, apparently you missed the brain rations day.
3. You're telling ME to go back to America when you're in line to buy food in McDonald's?? Why don't YOU go to America if McD's is so important to you. There are tons of them there...Oh wait, the way we line up may bother you to no end so nevermind.
4. I've paid taxes and National Insurance here for 20 years, idiot, so if I go back to the US, that's less money the NHS will have to reverse your lobotomy.
5. Are you on crack? Seriously, are you?

I think the thing that bothers me MOST about this episode is that if I were ever to say the equivalent to someone who had immigrated to the US, i.e. told a Mexican gentleman to get back on the boat to where he came from, I would be lambasted and hung from the politically correct gallows...and rightly so. But here it's perfectly acceptable to treat Americans like space invaders. I'm not saying there aren't obnoxious Americans out there, but please. So Angry British guy, if you're out there, just shut up and eat your Big Mac.