Forget the race issue. Yes, of course it's going to happen more in urban areas than it is in small town America. What's unique is that there's a lot of lone men engaging in it as opposed to groups of men which would be emboldened by the "pack" mentality.
Like the group of construction workers or, to dispel the race thing, a group of white bros in a passing car or frat boys out on the town. This is hardly simply a racial thing. Although I've noticed that black men tend to have less reservation doing this when the woman is black rather than white, but that's another conversation.
I don't know what the big mystery is here; we, as men should be saying these guys needs to grow up and shut up, period. Just because a woman's good-looking doesn't give you license to start catcalling her and coming on to her in the street, with no invitation.
Where is the disagreement here?