It's pretty wild to expect police to be this way, but in some schools young people can't even expect this much from teachers.
There are a host of reason for this that go beyond just "bad teachers." Schools set up in a way that makes this impossible. Just like police departments.
I'm certain these officers were following "policy" in their minds and that, had they made an exception for a child with clear adult support, (who wasn't wealthy or white) they could have consequences.