For what it's worth, I've been in the UK since about age four and everything I learned about the American Revolution took the view that the Americans were basically in the right. I don't know how typical this is, but if it is then one explanation (not the only one but maybe the most plausible) is that actually that's the conclusion most reasonable people would come to when looking at the available evidence, and the most plausible explanation of that is that actually the Americans were (according to typical present-day values) in the right.

http://www.gwern.net/Mistakes#the-american-revolution