Abstract photography challenges

I'm having trouble with the "abstract"-themed challenges (a general comment, not one specific challenge: hence no link). IMO, a lot of the entries aren't abstract at all, and I wonder how voters are ranking them.

I guess there's no absolute definition of abstract photography, but for me a conventional, non-abstract photograph represents some aspect of the things in the image, where an abstract photograph represents some idea or concept that is separate from the objects that are actually in the image. I'd be happy to hear a better definition from someone.

Like, with painting it's obviously easier to be "abstract", since you can just e.g. Jackson Pollock a bunch of paint on a canvas. I'm not sayin' it's easy to produce a decent abstract painting, just it's straight-forward to make an image that is "abstract" with that medium.

But with photography there is a challenge to make an abstract image with a medium that reproduces images of real scenes. I don't know if Andy Warhol's soup cans prints are strictly "abstract" (I'm an engineer so I don't understand that stuff) but they aren't about soup; but just adding some funny colors in PP doesn't make a landscape "abstract".

Joe