Why did the western powers follow a policy of appeasement

Because in the 1930s, Western democracies Uk & the French were desperate for the next war, & diplomatic authoritarianism was indeed a reasonable decision.

Explanation:

Throughout the 1930s French foreign affairs was dominated by the strategy of making compromises to executive powers to avoid confrontation. More certainly the Western governments pursued an appeasement strategy in the expectation that it would avert further War. It has been said that appeasement was advantageous since it allowed more opportunity for all the Allied to seek peace.

So, it's the right answer.