I figure he just hired a web site to be built. And then, didn't force his own pictures, so the site designers used stock.
Actually, he used his own pictures for most of the other workshops. For those locations where he used Shutterstock photos, he either never visited those places before or didn't have any competitive samples, for an eye catching advertisement.
On the other hand, I agree with you: most probably, he is not personally maintaining his website. He is a photographer after all, busy travelling the world and teaching students about "understanding exposure" and stuff
Therefore the technical mistake can most likely be attributed to some tech guy.
But he has certainly seen the website and approved it. He is the ultimate responsible for its content.