Heh, I remember that too. That would be metagaming if you were to do that (and I only got so abrasive there because a) he's my teammate, and b) I've known people to feel the way you did when playing games against him). The difference, as I see it (and a mod should feel free to overrule me in an official capacity, as this is an issue of site rules), is that you would have been making the fast elimination of Sandgoose your primary goal because you did not like him, whereas Germany here is making tactical decisions, likely based in part on English diplomacy, in part based on in game positioning and power balance, and in part on the past actions of a player he has guessed to be the English player, like you say.
TL;DR: This case is shady, but seemingly not metagaming. We should get a mod to make an official ruling as the TD's was based on an interpretation of site rules.