The other day, poet Matthew Stewart tweeted this, sparking off a very interesting discussion about the use of the first person in poetry, and the frequent assumption by readers (and Matthew was talking specifically about critics) that this is the poet themselves.
I don't have a great deal to add to it, but I do find it odd that this assumption gets made with poetry by people who have no difficulty in accepting that a first person narrator in a novel is not necessarily the writer themselves.
That said, I wonder whether it's also a question of degrees for poetry readers? If the poem is written in, say, the voice of a historical character, or an animal, the reader has no trouble knowing that the "I" is not the poet. Does the problem occur mainly when the "I" is not the poet, as such, but a character not that far away from them?