"Almost everyone." It's true, there were people who didn't, here and there. There were monsters who apologized, monsters who felt sorry for their actions. There were monsters afraid to FIGHT, like Whimsun. Monsters who regretted FIGHTing, like Toriel. Monsters who didn't FIGHT, but just...put them in the position to get hurt easily, like Alphys.

Those who didn't had their reasons. Very few of those reasons were out of any sense that they were Sparing the human for their SOUL.

One kid with a striped shirt and an eager grin, they...

One kid.

"Most of them felt bad about it after, but a lot of them tried."