Meh, if anyone was dumb enough to buy what must clearly have been rancid meat or mouldy food products then they probably deserve food poisoning. Seriously, if you actually bother to look at a piece of meat before you buy it, assess it for fat content, marbling, thickness of cut and what have you, as any normal human being would then you'll never get caught by this sort of thing.
If it looks bad, then it probably is. This butcher should not have put rancid meat out for sale, but he would never have gotten away with it if people didn't buy it from him. That and I highly doubt that he only sold mouldy food, there was probably fresh stuff there as well.