I never cease to be amazed by the infantile university left.
On this matter though they need to make their minds up. You can't find an academic nowadays who believes that the author should be referred to with respect to a poem or novel. We are told the author is dead, there is nothing outside the text, Derrida, Barthes, ya de ya de ya.
Yet this poem is unacceptable just because it was written by an artist the left dislikes. No-one has ever argued that "If" itself is in any way objectionable as a work of art. As a text.
Make your minds up, you can't have it both ways.