I'm a bit skeptical of their claim that "Human judges achieved much lower accuracy". The deep net likely found a some feature that correlated with sexuality presumably after looking at many tagged images.

I wonder whether the "judges" had access to that same training set. If they were people off the street that brought in their own biases, I would suspect they would do far worse than if they were able to view the training set themselves and teach themselves what hetero and homosexual people look like. Many heterosexual people have very limited contact with homosexual people. But given a training set (or sufficient contact with homosexual people), they could learn too, and I suspect they could learn better than the machine learning algorithm.

That said, this research is impressive, as well as terrifying and depressing.