There are definitely better ways to deal with a situation than violence, especially violence against a child. That man was definitely in the wrong.
That being said, where were this child's parents? Why would they put her [or let her put herself] in such a situation?
[ cue the
"you're blaming the victim" taunts ]
It would be interesting to see a broader view of the situation, like if the man was alone and surrounded by a hostile, opposing crowd. Or if he was just some crazy dude.