It drives me wild when people say stupid things like "Art is all subjective anyways" and "you can't define Art."
Both of these statements are completely false.
Art isn't subjective, it's intersubjective. Language and Money are also intersubjective, in roughly the same way. We don't agree, completely, on the definitions of words. We don't all have the same relationship with money, we don't all think about money in the same way. But we agree on enough stuff to get things done.
When you don't "get" some piece of art, that doesn't mean it's crap. It means that you're not part of the group that shares the relevant subjective experience. If you don't speak Spanish, this doesn't mean that Spanish is bullshit. If your corner store won't accept Euros, it doesn't mean that Euros aren't money. Get over yourself.
Art isn't even hard to define. There are lots of definitions out there, several in every dictionary. Before you get all shirty about how there are too many definitions, so you still can't define it, I point out that there are just about that many definitions for other words and yet nobody stands around like a dolt claiming that you can't define "Cat".
These things aren't even hard, and yet we see photographers mumbling around about these things like imbeciles every day.