But the idea of the peace movement started in the animorphs minds with 19, that was the first time they could say hey, not all the yeerks are evil, they are just "people" like us
I think in 6 jake didnt really see them as people, they were just slugs, like a little kid burning ants. He didn't do it for pleasure or anything, he did it for the mission because he ignorantly thought that was all they had to do, burn em and they cant get to the governor
Then he sees them as people and he doesnt want to burn them in 21, but more importantly, he had no reason to and doing it would actually hurt the mission. I still think he had progressed enough into the war to still be able to do it if he had to, despite his changed view of the slugs
Then 53, he just hated the yeerks, war had made him cold, he didnt care that they were just like humans anymore, so he flushed em
