He used leverage and futures contract plus of course others had joined in on the trade like some of the Arabs, so there was a swing effect and it smacked him in the mouth. Fairly sure he broke his own rules by using that leverage to buy silver, if he had balanced it by also owning a silver mine so all contracts he took could be hedged on some timeline then it maybe have worked. JP morgan does own a silver mine and with much chagrin sells silver contracts with leverage, they probably do quite well from that.
The relevance to bitcoin is that we saw recently fractional reserve bitcoin exchange breakdown and we may see other failures as people get the exchange rate to dollar wrong even short term. The main deal is not centralise that failure, the Hunts failed to propagate their idea beyond speculators. This is a shame as we've seen solid money is much in need and they were not wrong on that