Given German thought at the time I find that unlikely.
The author could have written: "We lost the war because Jews, Social Democrats and Communists backstepped us and not because we didn't have a good plan to fight two sides at once." He isn't that direct, but it's still the most reasonable reading for someone who writes that sentence in 1923 at a military academy in Germany.
I don't think I said what I meant, which is that the quote is a good example of irrational thinking.
Another month, another rationality quotes thread. The rules are: