The critique of the Spectacle is about representation replacing the thing itself, to the point where people no longer understand the difference between reality and representation. I suspect this porn is being presented to create a collective situation of aesthetic critique, rather than a substitute for actual sex (which presumably happens in private).

The idea that public sex is subversive is an interesting one. I suspect it comes from the idea that reversing privatizing - making the private public - is always good. In fact the existence of the private is not the problem, but the shifting of public goods into the commercial, which now presents itself as the private.