The Nazis only lost after several countries unified to defeat them. What would you have Poland do? France? When your only options are to lose or lose faster, compromise is the only possibility.

I said Neville Chamberlain, not the leaders of Poland. Poland had no recourse after being invaded by both Germany and Russia; and it didn't exactly help them, did it? Had the nations of the world stood up to Germany, it's likely they would have had to back down entirely. You're starting at the end. Germany didn't start off invading Poland; they invaded Austria*, then Czechoslovakia. Check out the Munich Agreement for an insight into how well appeasement works with the far right.

"At a Cabinet meeting on 8 September 1937, Chamberlain indicated that he saw "the lessening of the tension between this country and Italy as a very valuable contribution toward the pacification and appeasement of Europe" which would "weaken the Rome–Berlin axis.""

That turned out well too, didn't it?