I don't think poetry needs to be "easily understandable." First of all, there are often complexities of syntax, form, unfamiliar absences, etc., that require a deeper concentration than is usually demanded of us. So that, right off the bat, is a little difficult. Then there is the deeper issue of what poetry is really asking of us. I feel it is asking us to read with great, even sacred, care and attention. That, too, is difficult. It requires discipline and the creation of a temporary zone of privacy, which is inimical to our current conditions of life.
