The problem with this is that it's a team game, and your team could still win the game. It's quite possible that when you were defeated you did it in such a way as to impose a strategic cost on the opposing team, allowing your team to win. (Taking one for the team.) I don't see why someone who does that should not receive a win if his team wins because it is a team-based game.
I explained myself poorly, so I edited and reworded the original post. I was talking about when only one loser is left, after the rest of his team politely quit.
But I understand what you are saying regarding 'taking one for the team'. That's different, but I still think if he can't get a colonizer out, he should still be dealt a defeat. I believe after that, he still has the option to 'Keep Playing', and might still be able to help his remaining team win. But I still think he should lose (if no colonizer).
What we need is some sort of a victory condition...
and forcibly end the game.
Yeah, maybe they should add another victory condition/s (rather than a default condition).
If #1 & 2 were fullfilled, what to call the Victory condition? Maybe: Imminent Victory? No Hope? Extinction Victory?
And... I think this all may be related to not being able to achieve 'allied victory' in unlocked online games.