Yeah, it's an asshole move, but asshole moves are to be expected in such a high-stakes game. If someone works really hard on a project that fails, or doesn't do as well as he'd hoped, its definitely mean, and idiotic, to gloat. But, if in the process he gets to gamble tens of millions of dollars of other people's money, well, that's a different thing altogether. The project may very well still be his passion , he may very well work just as hard - or harder - but once he takes all that money that's a different territory.
If someone fails to finish a marathon after confidently convincing a lot of people to place large bets on his winning, I don't know if that makes it "ok" to gloat, but it's certainly asking for it.
To put it simply: when you run a marathon you want to be valued for your effort; when you ask people to bet on you, you're asking to be judged on the outcome.
A win or a loss, I understand there are some very talented, and nice, people involved, and I hope they won't let whatever happens to them affect their self worth, their true valuation, too much. They will still be just as talented and just as nice even when they choose to play a high-stakes game and lose and feel some humiliation, perhaps, when others do gloat for justified or not-so-justified reasons. It sure does sting, but that's life. A man's (or a woman's) true worth isn't measured by his success, and that's important to remember. People will gloat, though.