Embarrassed
It’s heartwarming to hear stories of people recognizing their errors and correcting them. Making mistakes is a vital part of human existence, but owning up to them is only for the strong of heart! Although bullying is inexcusable, recognizing you inflected pain on someone else is definitely a step in the right direction.
There’s really no excuse for bullying, but I think if the person eventually regretted the way they acted and apologized for it, there’s no reason to constantly bring it up their mistakes. Imagine always being reminded of how bad you acted when you were younger; we all deserve a second chance, right?