I think it's mainly because of the fratboy (correct word? :D!) culture you have over there. In my experience a lot of americans tend to be overly confident with themselves, which tends to make them more outspoken and then you get things like this (when drunk)!
Unfortunately for you guys that's very true. Obviously we are quite a reserved bunch, but everyone over here hates it with a passion. Even on the Skysports commentary, they are constantly complaining about it as well as Butch Harmon to be honest!
Here's the thing though ... so do we. And before you guys get too far off on your "Americans are a bunch of tools" tangent, also remember the math.
There are over 300 million people in this country and there are 45 PGA tour tournaments in a year.
In the UK, it looks like you guys have 7 tournaments, and 63 million people.
Also, don't forget that this guy is British ...