That's just it. They might regret they missed the chance, but only Tanya realized they had the chance and she couldn't convince them, so the ones who know about her attempts are regretful and the ones who don't want to overcompensate / take excessive risks to avoid further cases of it happening again.
I agreee. The weird thing is that, it wasn't as if the General Staff couldn't have dialed it back and come out with a statement of some kind to say publicly in the papers
no more agression with The Empire and we'll cut our losses.
It is alt history after all and this Germany didn't get dragged into conflicts like our IRL one e.g. Austria creating nearby smaller wars which caused Germany indirectly to be involved with the WW1 -- people like to forget that fact because wowie Germany Bad but they were dragged into it all due to a next door neighbor.
But here? The closeby nations are absorbed into the Empire outside of François e.g. the Rhine Front. So it's half the Zettour and Gen. Staffs fault for not understanding WW concept meanwhile Tanya is probably setting contingencies for when this happens.