Is poetry difficult to read by nature or do pretentious poets make it more difficult than it has to be? I think the answer is this. Poetry may be the most condensed form of written expression there is. Even a great poet’s attempt to pack as much meaning as possible into a single line can make the syntax hard to untangle. Then there’s the fact that the form became moribund in the later twentieth century, so much of the best work uses language we find archaic.
Beyond those two considerations, however, there is nothing inherent in poetry that makes it difficult to read. One of my favorite poems, in fact, is also one of the most straightforward.