For some people it being fake does ruin it. For a lot (me included) the idea itself is funny. When George Carlin was describing the first time he made a joke, the description described comedy to me. I don't know exactly what he said but along the lines of: the first time I told a joke it was to my mother. I made her laugh. It was the first time I twisted an idea in such a way that it was funny.

So yeah, two people can look at the same photo/scenario and the person providing a perspective that seems absurd and funny is the comedian. Sorry it's late but I hope I made sense.