>Then there shouldn't even be a draw option.
In a way, no. A game that is drawn is really no different from a game that continues forever. But eventually, you want to agree that it's not going anywhere and it's time to remove it from the list of active games (or go home, in FtF).
>I think in FS's and TB's view, a draw is equivalent to a cancel. That is, if nobody won, then it is as if we never played in terms of "bragging rights".
I can only speak for myself, but that's not quite right. I oversimplified a little in saying that the only goal is to win; I also have the secondary goal of not losing. The difference between a drawn game and a cancelled game is like the difference between divorce and annulment: we pretend that a cancelled game (like an annulled marriage) never really happened. So there are no bragging rights for a cancelled game; but in a drawn game, you might at least be able to say ‘I played against [insert name of good player here] and didn't lose.’, and you can also always say ‘I've played [insert number of uncancelled games here] games.’ and things like that. In other words, you can lose a drawn game, but not a cancelled game, so it's worth something that you played and didn't lose.
Actually, as far as bragging is concerned, there are lots of other things that you might say. You could say ‘I played against [insert name of good player here] and eliminated them.’, ‘I had a guaranteed win, but then [insert family emergency here], I couldn't get a pause or an Internet connection, and my sitter went CD.’, etc, and that might actually be worth saying (depending on who you're saying it to and why you're saying it), even though it's not about whether you win or lose.
If Diplomacy were as simple as tic-tac-toe, then every game (barring newbies and CDs) would end in a 7-way draw, and it would be boring. In that context, a draw is meaningless. But Diplomacy is not so simple, and you risk losing for the chance to win.