I assure you, no offense toward the wonderfully warm people of the united Kingdom was intended.
And, no, I would not "howl like an old lady" if someone were to good-naturedly poke fun at Bush (either George or Laura).
One of the traits of many of us Yanks is that we enjoy good-natured ribbing -- and we enjoy good-natured ribbing of our own leaders.
Sorry, though, that that does not seem to be part of your sense of humor.
I make an effort -- even though I do not live in the UK -- to understand British humor.
You might save yourself some grief if you make an effort to understand American humor before you assert that good-natured ribbing is "immature and nasty".
Just a suggestion, you understand, old chap.