On one side of the coin, I agree with you.
On the other, I don’t.
The KR were drafted at gunpoint. Comply or die was the basic recruiting slogan.
The scene described where the cadre were asked if the prisoners should be allowed to live was a standard issue ‘loyalty test’. Anyone that spoke up in favor of leniency would have been executed on the spot or held to be the center piece of a spectacle designed to terrorize any other cadre that might ever consider going soft.
Agreed — mercy seems the order of the day as an antidote to this. If you will repent, and you show it — share the mercy freely. If you dig in, as for a grudge — meet the consequences of dogged hatred.