there seems to be an obvious answer: publish the accuser’s name if the accused was clearly innocent.
What if, after all the evidence comes out, ‘Alex’ and Pat clearly both acted very badly, of approximately equivalent magnitude? In that case, Pat is not innocent, so your rule would say no revealing ’Alex’s real name, but then Avery still clearly got serious benefit (the negative information is much more weakly tied to their real life identity) from posting first.
What if, after all the evidence comes out, ‘Alex’ and Pat clearly both acted very badly, of approximately equivalent magnitude? In that case, Pat is not innocent, so your rule would say no revealing ’Alex’s real name, but then Avery still clearly got serious benefit (the negative information is much more weakly tied to their real life identity) from posting first.