I think it's true to say there was some "snobbery" as it said in the film that colour photography was regarded as vulgar at the time. There was also reference to the fact that black and white was the norm - and a lot cheaper than colour.
IMO, you've just got to admire the guy for sticking to his guns and shooting what he liked shooting, on the medium he enjoyed.
Having seen a lot of colour "street" work by the likes of Joel Meyerowitz and William Klein, I've been a bit ambivalent to whether colour works for that subject. However, having seen this film and the evidence that colour was a big part of the Vancouver "look" at that point in history, I'm definitely warming to it.