In one example the discrimination is deliberately performed by an ad supplier. In the other example the discrimination is performed by the audience of the offline publication. I come to this conclusion because it is the audience that is choosing which demographically targeted publications to purchase or read. People cannot legally discriminate against themselves.

That distinction is also a paradox for Facebook. You cannot be a supplier to everybody and simultaneously to a targeted individual as chosen by individual's inputs. Facebook tries to have both sides of a coin by allowing users maximum flexibility in content preferences and also provide that power to ad suppliers to use for precision targeting.