it's silly. Focus trapping..... nature literally triggers the camera. It's basically the same as what mr slater did. You setup a scenario that uses nature as a trigger..... so all of you hummingbird catchers, give up your photos, they belong to the public........
If you see the original language of the copyright law, it says:
"202.02(b) Human author.
The term "authorship" implies that, for a work to be copyrightable, it must owe its origin to a human being. Materials produced solely by nature, by plants, or by animals are not copyrightable."
this photo was NOT produced solely by nature. Mr. Slater himself said that he set it up. IMO, no different from focus trapping.
He has said that NOW, and that version where he set it up on a tripod and controlled the whole scenario, is no different from focus trapping so yes, copyright is applicable.
The problem is that the images were released with the story about the monkey stealing the camera. In that scenario, there is no human input and copyright does not apply.
The problem in Slater's case is the original story. If it is true, he does not hold copyright. If it was false, then he (or his agent) is an idiot for saying it because it removes the copyright.
Whether copyright actually exists on that image now depends on which story is true, and there is no point in us debating it as only Slater knows the truth. The fact that copyright is in doubt is entirely down to him (or his agent) trying to make more money by telling the world the original story.