There is in every madman a misunderstood genius whose idea, shining in his head, frightened people, and for whom delirium was the only solution to the strangulation that life had prepared for him.
This was said about Vincent Van Gogh, an infinitely awesome painter and a certifiably crazy human being. It could be applied to most any artist or poet (to use the occupations you mentioned) in order to explain their methods of expression. Art in its truest form is simply beautified insanity and the more accessible the madness the more people there are who can relate to it. It has nothing to do with the degree of culture and perception a person has, but with the experience he is willing to receive from the prospective exhibit.
That being said, I share your feelings on the state of modern art. A red paint bloch on a white canvas is not my cup of artistic tea, but it means something to someone and far be it from me to criticize their creative medium when I'm so imperfect. Who knows...I might see some exhibit featuring a toaster surrounded by barbie dolls from the 1950's and become racked with such intense emotion that I feint on the spot.
You said that some people are too willing to accept just anything as art...I think some people are too resistant to the idea of everything as art. I consider art as something that can compel a person to just stop and realize that the world around them is so mind-numbingly amazing...that way the definition of art is more up to the viewer than the creator. Even then, most of those who view a serious attempt at art will recognize the intentions behind the end product and at least respect the artist and his work.
Now all the non-artists and non-poets will think I'm an idiot...but whatever. I can see art in the way a homeless man stacks his empty liquor bottles...I can see art in the way a certain someone looks at nothing in particular...if you can see art in an upside-down urinal, more power to you, my friend.