Maybe the American opinion of the French has less to do with their behavior in subways, and more to do with the uncomplimentary opinion the French have of Americans.
Being software folks I think we can agree that people on cell phones "virtually" remove themselves from the public. Local conversations, either actual dialog or implied through gestures as when driving, are at the least diminished in richness if not fully squelched. You've just cited one of many reasons why the public is better off if they physically remove themselves.
Regarding the French, personally I have good memories of the people from my short visit. I was capable of speaking in broken French so that might have made all the difference. Honestly I didn't pick up on any anti-American sentiment though I did notice some non-French speaking resentment. Very different from some countries in the Middle-East I'd think, or just about any country in Asia.