There's significant documentary evidence of the incident on video, starting ~27:50: https://www.facebook.com/derk.brown.5/videos/154551737227670...

There's also some dispute about the legal disposition of the property on which protesters may have been protesting, but at worst it appears to be a private street. Just because it is a private property doesn't mean it was their private property, to defend with threats of lethal violence. Being a member of the HOA and paying your dues doesn't give legal title to treat property as your own.

https://www.facebook.com/kim.mason.716/posts/102190071407824...

And then, of course, that gate isn't destroyed in any of the videos from the scene. There are photos showing a destroyed gate - which looks identical - so it clearly was destroyed at some point. But the relevant question is whether that already happened before the confrontation, and it doesn't look like it did.

As for the guy's claim that he is a BLM supporter - you can judge the veracity of that for yourself, based on this:

https://www.fec.gov/data/receipts/individual-contributions/?...

(and then, perhaps, derive a heuristic to judge his other claims)

I’ve seen no evidence of guns from the protestors, just the racist Karen and Ken.

https://twitter.com/averyrisch/status/1277398535973949440

So no, not a "standoff". Such behavior is certainly sufficient grounds to dismiss any claims of self-defense - lethal force is justified in self-defense when a reasonable person would perceive a threat of imminent death or significant bodily harm; but if you believe something to be a source of such a grave threat, why would you run at it?