Herman Melville's poetry

I was watching a lecture Helen Vendler was giving on Yeats's "Among School Children" and she referenced a poem by Melville, quoting

"What Cosmic jest or Anarch blunder

The human integral clove asunder

And shied the fractions through life's gate?"

I rarely, if ever, see his poetry mentioned. I have been reading some of it over the last two weeks and I think it is wonderful, making me wonder: why is his poetry seemingly forgotten?