I think you are wrong. I agree with you, in the sense that I would not feel comfortable doing this. "The gun is always loaded" is great rule, as is "Never point a gun at something you don't want to shoot". But it has its limits, and context is important.

Assume that you're a hostage negotiator, or someone in the police or military that otherwise expects to end up in a situation where someone is pointing a presumably loaded weapon at you at close range. I think there's a good argument to be made that you should train for this circumstance under the most realistic conditions you can muster, rather than hoping that your first live experience will go just the way it did on paper. If having a real gun pointed at you helps to simulate and train your real life response, this might be a good strategy.

Personally, as someone not in such a field, I'll spend the bulk of my efforts on figuring out how to avoid such situations. But for a professional training for a situation they expect to encounter, this is not 'play'.