Answer:
see below
Step-by-step explanation:
I agree that the Purification Movement was a major error of judgement by Chiang Kai-shek.
I would argue that, above all else, Chiang's motives for initiating the movement were to eliminate his political foes and consolidate his power. He saw himself as a leader who could unite China, but he had no way of knowing how to do so—and so he chose to eliminate those who disagreed with him rather than trying to get them on board. This is especially notable because many of these people were actually on board with the idea of unification—they just didn't think it should be under Chiang's leadership or rule.
The impact of the Purification Movement was devastating for China in general and the KMT in particular. The KMT lost a lot of support and legitimacy during this time period, both among its own people and among other nations around the world. It also caused considerable economic damage as people lost jobs and property due to persecution or exile from their homes and communities.