It's justified because as we see on the video they were hurling racial insults and taunts, he had a reason to believe his life could've been in danger especially considering how one of the men was standing by their car as if they were looking for something, possibly a weapon.
The situation gives probable cause, unfortunately, Walton County must be a “redneck country” in that particular area of Florida. On the surface, just being a Black man in possession of a gun firing at two whites is enough for narratives to get twisted and that is why he's wearing state property.
The Court/Law system doesn't believe you because you're Black and supposed to be wrong and/or lying, on top of White people in the area learning and hearing about the story spinning the narrative to make you look like the attacker.