I think we have two different concepts here. Strictly speaking, spoiler information would be some knowledge about the game you are playing that you should not have available yet ... location of a resource, what is hiding in the fog of war, who your opponents are that you have not met yet, etc.
But what we are talking about here is knowledge of more generic performance information from a game in a "parallel universe" ... score, culture and power of teams playing your position in another game. A somewhat different animal.
So the question is does this performance information from a parallel universe provide some unfair advantage to some teams? Does knowing what Ragnar's or Gandhi's score is really tell me where to move that caravel? Or whether to build that library or that axeman?
I think that the performance information does not really spoil the game, and to me part of the fun of the SGOTM is to watch the score graphs progress. I don't see adding Gandhi's score as any more spoiling than showing Ragnar's score, but then if most are bothered by that, I can live without it just as well.
dV