Built in way to remove default moderators group from About page?

[nathank (Nathan Kershaw)]

@one1

That means that there is no (forum software) group for these trainees. Therefore they can’t be excluded as a group.

You could use the well written and quite stable Discourse Dynamic Groups Plugin to dynamically populate a group of ‘not-active’ moderators - and hide this group using the setting above. That would achieve what you are after I think.