I was reading your rant and went through the same thing, except I was in England!
Every time I go over I end up having some very strange experience, and it always starts with my "accent".
Try to order an Iced tea in a local pub, that was a fun and very long conversation!! I can't remember how many times the guy at the bar asked me to say antibiotics.
Then we had the washroom incident with the very scary lady, not sure how I made it out of that one without hurting her!!!
I guess my point is that your "accent" is relative to where you are in the world. And from what I've learned is that it's a certain kind of person that does this, not a group as a whole.
Most people were very polite, but did ask where I was from, funny all guessed the U.S. and only a few were rude/annoying about things.
Now how's going to share that deep fried Mars bar?????