Ben Lerner in his recent book of this title claims that we overvalue Poetry with a capital P, all of our dreams about what Poetry can be, and undervalue actual poems, those imperfect and hence detestable reminders of our failure.
The gap between poetry I (our ideal of what it is) and poetry II, actual poems, produces a syndrome called poetry hatred.
I would like to suggest a different twist. I believe Lerner is correct, but only partially. There is a poetry III: actual poems that do exemplify what we think of as poetry I. The hatred of poetry surges in me because of hundreds of poems one encounters, only a few are actually fully present enough to justify the grandiose claims of poetry I. Your friends' poetry is not going to be very good, on average, and neither is your own. The whole social aspect of poetry, the idea of having a community, falters on the fact that you are betraying poetry all the time by allowing poetry II to stand for poetry I and III, when it really does not.
Social and institutional pressures force us to recognize vast swaths of mediocrity by famous poets as poetry III when it is really poetry II. But poetry cannot exist at all unless we have enough of it, even the bad and mediocre stuff. We need it to produce the conditions in which real poetry can emerge.
Lerner admits at one point that he is not going to look at the actual good things good and great poems can do. That is the missing piece in his argument.