I think that the real problem here is not that the player surrendered to someone other that than his aggressor, which is a valid tactic depending on the situation, the problem seems to be that he essentially surrendered to himself.
He surrendered to the number two player and then took over that player, possibly controlling more power than he did previously. What should have been a selfless act to preserve the Last vestige of his population was turned into a cheesy manuver to get more power and a fresh start without having to work for it.
Surrender is itself an act of defeat, whether it is a reward to a conquoring empire or as a Last ditch attempt to preserve some of your accomplishments by entrusting them to those you would consider a kindred spirit. Whatever form it takes it is an acknowledgement of the fact that you were not strong enough to survive on your own.
When this is 'faked' in a craven bid for power it cheapens us all.
My melodramatic ramble now comes to an end.
