Ahahaha, you Yanks with a w stole and perfected our language, the clue is in the name "English", not "American".
I should learn to spell.
There, fixed it for ya. Of course, we Yanks gotta fix a lot of things for you limeys from 1776 onwards.
See, we figured that since "honour" and "colour" and other words originally from Norman French are no longer pronounced in the French fashion, we would drop the "u", as it doesn't make much sense given standard pronunciation rules in English. You guys are just holdin onto the past. Like an old lady still usin Jean Nate and watching Lawrence Welk reruns on PBS.
As for Americans stealing and bastardizing English, we just made it better and more efficiant without all those extra 'a's and 'u's!

QFFT!