Some people have claimed that Baldwin should have made sure the gun was clear. That doesn't work, because the gun's not supposed to be clear... it's supposed to be loaded.
Some people have claimed that Baldwin should have been able to tell the difference between a dummy round and live ammunition and made sure he knew what was in the gun, but apart from the fact that he's never going to be an expert in that -- and the fact self-described experts can't visually tell the difference -- the whole point is for the props team to provide as realistic looking and feeling props as possible, so if they did their jobs right, it may not even be possible to visually tell the difference.
Some people have said he should have never pointed a gun at the camera/operator... but we have people point guns at cameras all the time in films, because POV shots of guns pointed at the camera are very effective in showing intent and danger to an audience.
Fundamental rules of gun safety are great when you're trying not to hurt anyone, but they're kinda shitty if you want to make it look like you are trying to hurt or kill people.
Never point a gun at anything you don't intend to kill? Nope.
Always keep your muzzle down when not aiming at a target?Nope.
Never put your finger on the trigger unless you're ready to destroy? Nope.
The reason films use armorers is that they want to do those things as safely as they can with guns that are as realistic as possible -- which often means real guns with fake bullets, or guns that have been rendered non-functional in some way. If you need a gun to shoot blanks, it has to be functional. If you want to showcase that gun being loaded or look up a barrel with a round chambered and ready to fire, you need to have something in it that looks like a real bullet.
It should never ACTUALLY be a real, live bullet, but through a lot of negligence, that seems to be what happened here.
That's not Baldwin's fault. It's the armorer's fault.