As I have written before, IMHO Gervais is a vile man, and I would not spit on him if he was on fire. However, in all fairness he could not have been expected to know that there was a couple in this situation in the audience.
What is galling is that he knows now, and he has stayed silent. The late Rik Mayall once told a very bad taste joke , and upon realising that he had gone too far, he then publicly apologised. But then Rik was by all accounts a rather nicer person than is Gervais.
Gervais has made a great deal of money out of being an unpleasant prick. I congratulate him for exploiting a natural talent if nothing else.