Ya, this article doesn't really make sense in this particular case as an explanation for Bitcoin's behavior. Though in general I do agree that shorting is important for the health of a market, this Bitcoin bubble played out exactly like every other Bitcoin bubble, and in all those previous cases shorting was as difficult as its ever been (which, actually has never been that hard, to be frank - people always insist that shorting Bitcoin is so hard, but it's not at all and never has been).