There’s no evidence he had any idea of the race of the young man before opening the door and the report wasn’t that the kid was simply knocking, he was banging and apparently yelling which set off the alarm.
This is also a home that had already suffered multiple breakins in a neighborhood that had as well.
That scenario would put anyone on edge at a minimum and quite likely induce more than just a little paranoia.
The guy was in the wrong the moment he stepped out to pursue the kid, that was assault with a deadly weapon, and he aggravated the felony by unlawfully firing the weapon.
He’s headed to prison where justice will be served so just what more are we supposed to hope for here?