According to whom? Why do stuff like invade Belgium?
It’s always been about dominating the continent. This time, with the EU, they got it.
Even Fritz Fischer’s book on German war aims in WWI (which is in no way complimentary to Germany) admits that they entered the war with no war aims. The reason for the attempted “knockout blow” in the west was because the German High Command felt that they could not win a protracted 2 front war and that the best bet was to defeat France before Russia could mobilize. Russia mobilized faster than expected, though.