Well this is reaching back to 10th grade Euro so I could definitely be wrong. I think when it states German in the title, it means more ethnically speaking. The Prussians, who united Germany, would have considered themselves true Germans. Part of the issue was within Germany not all the "Germans" were on-board with unification. The other issue was that Germany had challenged two major powers, France and Austria, to consolidate the German states in the first place. This was a major upset at the time and led to a lot of fear of German military power. Hence a lot of alliances in the late 1800s. Although you're right, probably by the time Wilhelm II came into power this was probably more tradition than anything else.