You're right that the people gambling on BTC are playing a risky game, and maybe they should expect events like this. Likewise, however, a startup flush with tons of capital that can't be bothered to even reply to its customers' support tickets shouldn't complain when people warn others away from them. (Although r/bitcoin is probably a better forum than Hacker News).
Regardless of their TOS, they know full-well that customers use their platform to speculate. If they can't handle high-value financial transactions properly, or at least respond to their customers when things go wrong, then they shouldn't play the game either.
> 3.5 When buying or selling bitcoin, you are buying or selling from Coinbase directly. Coinbase does not act as an intermediary or marketplace between other buyers and sellers of bitcoin.
> Coinbase may cancel or reverse potentially high-risk buys or sells of bitcoin, including those made using reversible payment methods.
Could very easily be that your transaction was flagged and then reversed. Your BTC was returned in full. If the price had gone in the other direction I doubt you would be offering to compensate Coinbase for the difference.
I have also been held up by coinbase delays in transactions over the last few days (though nothing was reversed), so I empathize with the pain. If you know of a more reliable and more quickly servicing online bitcoin exchange, I know many who would be happy to hear about it.
There was a story yesterday about someone wiring over tens of thousands of dollars and not hearing back for 1-2 weeks.
My theory is that Coinbase are performing some kind of proprietary trading and have burnt themselves badly, and to recover losses, they are front-running customers and delaying trade settlement.
You're the one gambling money on an unproven digital currency, created by an anonymous person on the internet, via an unproven and completely overwhelmed little startup. If you can't handle losing money on a failed transaction then don't play the game.