A poem only truly exists in the mind of the reader. A poet knows something about some place in a reader’s mind, and writes a poem that leads them to that place. The best poems find a place that exist in almost all of us, and that leads us leads us to agree that it is good, or even that we like it.
I see people whose second language is English post poems online that, I hope, are written by someone else whose second language is also English, and find myself having no clue as to what the poem means, or which place that author has led the poster to. I have no problem with this; a poem that finds just one other person to excite is never a bad poem. But I look at the words and wonder, what is their understanding of this language of ours? If I write a poem that they like, will I have led them to the place I expected, or are they someplace else that I can’t begin to fathom?