My view on the whole moderation argument is that as long as Dave Leip assigns you to a board, you have a responsibility to us to moderate that board until he moves you off.
Well, probably at least a third (half?) of Atlas mods either don't moderate anymore, or go through long stretches of time without moderating. Heck, Lunar is still a moderator of Individual Politics, though he hasn't posted since 2011 (and attempted to resign his position back then).
Folks have tried to resign many times, only to see Dave ignore their emails, so expecting them to keep at it indefinitely seems like a big ask.