...It would've followed them? Even if a single person left, Celestia would've endeavored to punish the individual, no matter how long it took?

[ It wasn't unusual, for gods to take extreme measures against a threat. And...that's why it was difficult for him to understand.

Because he didn't see anywhere that indicated that there was a threat against the gods. That these people acted as harbingers of darkness or summoned demons or monsters of the like. ]