Expertise is not the requirement. It is incumbent upon anyone who handles an item known to be potentially dangerous, and firearms meet that description, to know how to do so safely. In the case of firearms, that means to be able to check whether it is loaded, to not point it in a dangerous manner, and to not press the trigger except when it is appropriate.
The occupation of the operator is irrelevant, as is the purpose for which the item is being used.
That won't cut it.
When there are people who cannot safely handle an item that is known to be inherently dangerous, it is necessary to secure such items and keep such people from handling them.
We do that at home; it is done in gun stores; and it is done at ranges and around the campfire.
It's easy to be an armchair expert, isn't it? Like I said, an actor likely doesn't know what he doesn't know. It's easy for you to sit back and attempt to "educate" us on the forums, but I suggest you go do so in Hollywood since you seem so sure of how things should be done and let us know how that works out for you. And I'll be rooting for you, but I suspect you'll get a lot of pushback and find it not so easy to do things "the right way".