My understanding is this: Hooft is an "instrumentalist" as described in this article. He does not believe that quantum mechanics describes "what's really going on" and is interested in classical models that explain why QM makes such good predictions.
"Superdeterminism" is a very interesting perspective that Hooft feels could resolve this dilemma. Others feel that superdeterminism is not falsifiable, so there's no point in discussing it.
I came across this interesting article on stackexchange from a few years ago: http://physics.stackexchange.com/questions/34217/why-do-peop...
The first response is from Peter Shor, presumably the discoverer of Shor's algoithm. Kinda cool that such intelligent people with the highest academic credentials use a public forum.