If someone has better info than this let me know but my assumption about why he opened the place at 3:30am is that it was in fact 24 hours, and that the employee had gone on break.
I think these guys probably arrived during that break and got pissy the doors were locked, and instead of politely, patiently waiting for them to be reopened decided to yell and scream and intimidate. Should the guy have kept them locked at that point? Maybe. But if the store is meant to be open for business again, and his break's over, I can understand why he'd just sort of be like "okay motherfucker, come on in, get what you want and get the fuck out" hence his hand motion for the guy to come on in.
But the guy couldn't just leave it be and had to keep up his shit, and then throw a punch.
I'm glad he got shot and I wish he would die.
No room in civilized society for his type, and they are all too common and getting moreso. At some point I think a decision will have to be made, keep a civilized society, or keep people like this around. I know what my vote is. (And no, this has nothing to do with the guy's race)