I've seen and experienced this hundreds of times, and this dynamic has been written about and described by folks way more articulate than me.
It has been theorized that the "slow crossing" behavior is a way for people who feel disenfranchised to assert some type of power or influence over those who they feel are their oppressors.
It's a sociological behavior, but to me it screams "ghetto hatred".
Yes, I’m sure that’s what it is, just a sort of passive aggression to let us know that they can have some control over us. I don’t know that I wouldn’t have the same attitude if our roles were reversed. It’s poor form to criticize or judge when you one hasn’t walked a mile in their shoes, as the old saying goes.
I am seeing it traffic, too. The light changes and they just stay there, and when they move it’s very slowly. Almost like they’re hoping to get a rise out of you.
It used to frustrate me, but then I realized I wouldn’t change places with them and if that gives them some feeling of control over their lives it’s no big deal to me.
I wish I knew the answer!