Call it savage or brutal, it is what it is. A beating for trespassing on someone's family in one of the worst ways you can. It is not 'Sadistic' though.Replace the word "sadistic" with cruel, savage, brutal, vicious ect. The point is that at some point in that beating, it stopped being about protecting someone and became about metering out punishment.
Of course the this situation and the Zimmerman situation are completely different, but the people saying they would do the same thing as this guy, all contribute to the same culture of disregard for the law that was present in the Zimmerman case. You can't cleanly separate the two.
And I'm really, really failing to see how you can't cleanly separate being committed and ready to defend your family without waiting for cops to do it for you, maybe, is the same as prowling the streets with a gun and stalking anyone who looks funny.