One reason people can have different opinions about this situation is that there may actually have been a valid movie reason he pointed and fired a gun directly at the people he shot. I guarantee it was not the actor’s responsibility to check that the gun was properly prepared for that scene. Expecting actors to be competent to check every stunt and prop is unreasonable.
The difference is that movies are not real life, and in movies actors are sometimes expected to do things that would be catastrophically stupid in real life. They are, however, assured by experts that it will be fine and they needn’t worry. In one play I was gun wrangler on, at the end of the scene the actor notices the audience has witnessed his murders and points the gun at them and fires directly toward them. This was okay because he was given a top-firing blank gun and the stand-off was appropriate. It was safe because I had selected the correct gun and walked the actor through the proper way to handle the gun in the scene, and had he shot someone somehow it would have been my fault that it happened, not his.
Totally possible he was doing the wrong thing too, however. We don’t know yet.