Officer probably got a call from a neighbor. Saw a vehicle parked in the street and a guy hanging out in front of someone's house - he wasn't an owner or a tenant. Officer has every right to come onto the property and question the guy. Guy never gave his complete name, just grunted out Pastor Jenkins live across the street. He was all ready to pick a fight with the cop, which is exactly what he proceeded to do.
If I was on the jury, I'd come back with a verdict of "guilty" for watering-guy and fine him $1,000 for being a dick for no good reason. Oh, and $000,000,000.00 for his "civil rights" violation.