I do. He didn't have to shoot. Pull out the gun, tell knife guy to stop or I'll shoot or say "make my day", or whatever it is cool gun guys say these days. if he keeps coming, then shoot. It's what we expect from the cops and we should expect it from civilians too.
"But it's fight or flight, his adrenaline was going and he went on instinct". If he can't calmly use his gun he shouldn't have one.
People here are saying "now he's going to feel guilty the rest of his life for shooting that guy". Well, that's what he did, so he should feel guilty.
To be clear, I think pranks are dumb and I want youtube pranks to go away, but people walking around with guns is dumb too. They can both be dumb.