While you're right, this all happened after Bismarck and the pre-WWI German government had put a lot of effort into avoiding a two-front war because they did not share the General Staff's optimism about being able to handle it. So this constitutes failing to admit losing a very high stakes bet, and does seem inherently irrational.
My impression is that the German military was never optimistic concerning winning vs England, France, and Russia. Those that claimed WWI was deliberately initiated by Germany, however, had to falsely claim that the German military was optimistic.
Another month, another rationality quotes thread. The rules are: