So Germany has to be the aggressor? Seems a bit biased.
No, it is not biased but just logical.
Without a french-russian alliance, there is no sufficiant balance to Germany's power in Europe. So Germany, which under Prussia's lead is very militaristic and imperialist, will have a strong incentive to use its supremacy to furter its positions and advantages in Europe.
That's why some kind of french-russian empire was going to happen anyway.
In history as in alternate history, as I already mentioned, one can't bet on perpetual stupidity of the other players. Sooner or later, the domination of one power or one camp will arouse an alliance to counterbalance it.
That's what Bismarck, who was a political genious, had understood. And that's why he advocated that Germany self-restraint in order to prevent such an unavoidable outcome.
The other point, at least as important, was that everybody knew or should have known (it was obvions from 1688 on), that Britain fundamental strategy was to prevent any power becoming dominant in continental Europe.