This makes the 3rd or 4th time you've mentioned the fact that the individual was a teenage girl. Is this important to your argument? Are you saying that you would feel differently about the incident if it involved a middle-aged woman?
Duh.
If he had been 100 meters away showing himself to an old woman it would be different. Since he was in close proximity on the subway and it was a teenage girl, yes, it makes a difference. But that's why some of us get paid to exercise judgement and discretion and you get encouragement to go out and meet living women, it is because you don't understand why what happened is criminal and not just offensive.