hedwards: A broken clock is right twice a day. I'm not so sure they would have been so focused on it had he been something other than American.
Actually, it wasn't the fact that he was American, but that he was somewhat of the biggest asshole ever putting his ass on a bike. A friend of mine is a huge cycling fan (still, surprisingly) and he said that Armstrong was generally disliked by most bikers and the whole "cycling scene" because of his attitude and personality. (Eg. When you competing for the win and the closest competitor falls, it is customary to wait until he is back on the bike. Armstrong didn't do that, he drove on. Or that he
only drove the Tour de France and not the other races).
Armstrong was probably seen more negatively than many others, but not because he was
American, but because he was an
asshole.
And on a personal sidenote: I only ever hear from Americans that the French don't like them. The French I met in my travels or that I know don't look especially bad upon Americans (most are actually very positive towards the US). The most common "target" of the French is and always will be England.