Why dont you really understand poetry?

[sayingtest]

i know you wanna say you do, but just becuase you know that people who sell poetry these days are like you doesnt me you understand poetry,. you understand things that some one like you could understand even if they heard it from you

[Grannyjill]

This is an extremely muddled question. Who are you asking the question of? I understand some poetry, I don't understand other poetry. Some poetry is quite straight-forward, some poetry is very complex. Some poetry may need explanation because the writer has had experiences we do not share.
The people who sell poetry books are in the business of selling books (obviously) so they produce anthologies etc. which they believe will sell. If you imagine a book of poems in the same way as a CD - then what appears in the compilation must be appealing to certain people - otherwise no sales would be made.
If you write poetry that no one understands or likes - then by all means keep on writing (but don't show your poetry to anyone) unless of course you are prepared to see where you could improve or change. If you don't want to improve or change - carry on writing for an audience of one -you.