As GLoC alluded to, there is a difference between "Americans," "America" and "American policy." With the possible exception he also cited (and for the same reason,) Britain will likely be our closest ally for the foreseeable future. We took their traditional commitment to individual liberty to its logical extreme, with the result that, if Britain is too much like (the rest of) Europe to completely agree with us, they are too much like us (or vice versa) to completely agree with (the rest of) Europe.

My guess is US policy, specifically the Iraq war, hurt our British standing. Using 911 as a pretext to invade a country that had nothing to do with 911 hurt our standing everywhere, but we had more ground to lose in the UK. Romney did not help when he showed up for the Olympics telling them they were running it all wrong and Al Qaeda would murder them all. Yet the Iraq war singlehandedly brought down the previously very popular Blair government, and that is very revealing.