It's somewhat of a recurring nightmare for me to have some car-driving two-legged sphincter harass and provoke me to 'that point' while I'm out with my kidlets. It would scare them to hysterical tears, I know -- yet I want them to know to stand up for themselves, and not be bullied by fools.
Not everyone will have the same answer to that given situation; I don't think I'd have handled it as civilly a the OP. Doesn't make either of us the more correct.
One thing I think we all DO agree on -- that poor kid!