Well, I could imagine that if the black and hispanic kids were uncomfortable and chose not to high-five the cops, then over time what could evolve is the cops high-five-ing only the white kids. Even though that wouldn’t have been the cops’ intent, the appearance could indeed make the program “ineffective”, to say the least. Maybe that’s what was happening?
The reason they stopped is because other people decided that it was offensive to black and hispanic kids. I think it’s pretty sad and upsetting that children of any color would be uncomfortable with the mere presence of police officers that are trying to be nice. It’s a good opportunity to encourage mutual respect between police and ordinary citizens but we can’t have that.