I don't really have an opinion of the McCloskeys as people, but there's certainly nothing wrong with trying to defend yourself and your property from trespassers who broke open your front gate and threatened you.
Didn't they "break open" a gate to the neighborhood, not something that actually belonged to the McCloskeys? I think this distinction actually makes a pretty big difference in how unreasonable their actions were.
Even if they didn't actually own the gate, it was still right next to their home. On top of that, the protesters were still trespassing on private property (meaning they shouldn't have been there regardless of whether they broke open a gate or not), and at least one member of the crowd directly threatened to kill them. With all of these things taken into account, I'd say the McCloskeys' actions were reasonable.
So it turns out the idea that the protesters tore down the McCloskey's gate to enter their property is false. The gate belonged to the neighborhood, and there is also video confirmation that they just opened it up and walked through without breaking/entering. The gate did end up broken so, maybe someone near the back of the line vandalized it or something, but it's a little different than the way the narrative is portraying it.
Next, it turns out that the idea that the protesters trespassed on the McCloskey's property is exaggerated and potentially false. Yes, they did trespass in the neighborhood since they weren't there by invitation, but they were walking on the streets and sidewalks. The crowd was in the neighborhood to protest at the mayor's house and no one knew or cared who the McCloskeys even were. The only connection is that they happened to walk by their house. I obviously don't have access to the property deeds to ensure that no protester set foot on any McCloskey property before the confrontation, but if they did it was inadvertent and inconsequential.
Finally, the idea that it was a violent, angry mob who threatened the lives of the McCloskeys appears to be false, at least almost entirely false with vanishingly few exceptions. The crowd was by all accounts peaceful until the McCloskeys revved it up by threatening them and pointing guns. Some protesters said some ugly things in response, including at least 1 threat on the level of what the McCloskeys were throwing at the protesters. However, had the McCloskeys just stayed in their house, the protesters would have just kept on walking by and everything would have been fine for everyone, because as I pointed out, the protesters weren't there for the McCloskeys. They were walking past that house to get to the mayor's house.
I'm just not seeing anyway for the McCloskeys to be in the right on this. The protesters had nothing to do with the McCloskeys until the McCloskeys decided to have something to do with them, and it was the McCloskeys who escalated the encounter to include threats and pointing guns. The fact that the Trumpist side has to make up a fake narrative about them in order to have a competent-sounding defense speaks volumes.