All the speaker of "Introduction to Poetry" wants is to communicate with his students. But, for whatever reason, they just aren't feeling it. Language may ultimately be to blame. See, the teacher and the students are using the same tools (words) but with very different understandings of what those tools are capable of. Most students, when they see a bunch words together on a page, look for what they think is the end product of weilding those tools—meaning. That's what words are for, right? Right. But words can also be used to communicate feeling—the way an abstract painter uses color or a jazz musician uses sound. Sure, a hammer is for pounding nails, but it can also be an axel, a fulcrum, a paperweight, or a murder weapon.
The lesson of this poem is that poems should communicate both intellectually and emotionally. We should understand them and feel them all at once.
Poets should start using emoticons.