Hold on, nowhere did I say that A and B corresponded to the Germany/Poland situation. You are putting words in my mouth.

I was strictly illustrating a counter example to the implied notion that overreaction implies suddenness.

To further demonstrate that this is a misunderstanding on your part, it wouldn’t even make sense for me to have A and B correspond to the Germany/Poland situation - that would make my argument circular!

It isn’t very kind to take an interpretation that would set the speaker’s argument as circular, when an alternate and trivially-demonstrated-as-more-valid interpretation is also available. I believe the advice is often stated as - assume good intent.

On your second point - this is an elementary school tier interpretation of history. Poland itself did not have anywhere close to sufficient leverage to make such decisions about delaying negotiations. They were able to do so solely due to Britain’s backing their decision with force. Why did Britain back them? Why do you believe the history book written by the winners so easily on a topic so fuzzy as motive?

I didn't though. I illustrated that overreaction can be extremely sudden by being just that, an overreaction. Because gradation is expected, overreaction is unexpected, which, if my English isn't too rusty, is a synonym of sudden. I'm sorry you thought I was putting words in your mouth?

And I'm not a huge fan of Weinberg (and most pre-2000s historians), I think he was too 'furetien' in his vision of Nazism, but everything he wrote was backed by facts and actual written sources, and that Poland (and most of the world, including Romania) was more than miffed by the destruction of Czechoslovakia a year after the Sudetenland was annexed is a fact, and more than a few diplomatic cables show that.

Also, Beck was quite convinced of Poland's ability to hold until the french attack on the other side, and thought USSR would come to their help (especially after Memel, and probably because the French were persuaded of it too), thus convincing Carol to throw himself with the 'peace Front' (hindsight is 20/20, and Ribbentrof the most competent Nazi, probably because he was not ideologically one, which helps). England actually pushed for Poland to make concessions, and multiple cables from Poland responded to the English in the summer 39: 'we want, but they won't meet us'. I think they threw a last hail Mary: fully open borders in the area (no treaty at all, just a policy change) to show that they were open to negotiations, but it was too late.

To respond to your actual question, Britain backing was in name only (compared to France), and mostly prevented a France-Poland-Ussr alliance originally (after that Daladier came back USSR alliance was a bit farther, than anticipated, but still). Britain (and US) were aware that Germany was stronger than France, but thought the gap was small and tried to limit French diplomacy to keep it that way (limit continental European powers was a major mandate). They misjudged the balance of power. But they certainly didn't pit Poland against Germany, pushing relentlessly for negotiation instead, unlike the French