I agree with the first two paragraphs in the quote.
As for the rest of the quote, has anyone done some statistics on collected data? For example, if a spider x normal mating produces three eggs and all the babies are spiders, it doesn't mean much. The odds of that happening by chance is 0.125 (one in eight). But if that mating produces 13 eggs and all the babies are spiders, the odds are different -- 0.0001 (one in 10000). With that kind of number, I would give serious consideration to the spider being a super spider.
I do not think that the breeders are lying. But they might not have sufficient information to give us the correct conclusion.