I'm sure, at 15 feet, the thugs looked bigger and more menacing than they had climbing into and out of his neighbor's window at a distance.
All we can hope is that Mr. Horn didn't use the "n" word (forensic audio scientists at the FBI are likely scouring the 911 tape as we speak) as he pulled the trigger, because then, he's TOAST.
As we know, that would then become a MUCH worse thing than merely killing the criminal thugs, it would be a HATE crime against two minority members of society just trying to make a decent living. /sarc