They probably get mad because she's wrong. lol It's no different than someone saying "in their opinion" Mars isn't a planet because there's no people on it. Reminds me of that John Oliver sketch where he says not everyone "gets" an opinion. Google John Oliver, are there owls? It's funny.

Mary Oliver's Wild Geese has more rhythm and flow than a lot of "rhyming" poems and not a word of a rhyme to be found. Also? Does that mean nursery rhymes are poetry? lol.