I can see how an old decadent culture could misinterpret competitiveness for cruelty and self-confidence as arrogance. We look people straight in the eye and shake their hands as an equal. Many cultures don't. American have historically been known for their passion, curiosity, vigor and robust enthusiasm. The Brits seem a reserved, "pinched" and whiney in comparison.
As far as vulgarity - have they never heard of Benny Hill and Carry On Theater? Talk about baudy. I would say that, in comparison, Americans have chucked the art of Victorian innuendo. We are right out there in a matter of fact way, thanks to Hollywood. I will agree, it is not as funny an approach as oblique references to "naughty bits." I personally prefer the Victorian style.
I will agree that money is the prominent American measure of success. Perhaps because it is a competitive measure and does not drag up historic memories of privileged classes with inherited wealth and power. Entrenched class structures would appear to be far more a British than an American thing. I would think Americans would think that Brits are far more aware of institutional class strata than Americans. (Think Queens, Dukes, Duchesses and Sirs.)
I think the perception of racism and crime comes from the MSM. I don't see it as a prominent reality out in Red State America. Is this a by-product of pictures of Katrina?
England is still a class-ridden society, suprisingly so.