What does this poem mean? T.E. Lawrence - Dreamers of the Day?

Lawrence is saying that dreaming at night appears fatuous when dawn breaks and that those that 'day dream' are dangerous. But that seems nonsense to me. However, Lawrence also uses the word 'visions', which are entirely different to dreams. We all have dreams but it is the visionaries that achieve so much in this world whether through making a personal ambition come true, such as writing a novel, or changing the lives of millions - so the title in my opinion is misleading. My question is: is this a poem or a piece of prose. I see no structure in this piece although it is well written but it is prose, it is not poetry.