User blog comment:Thailog/Ep. 126 "Auld Acquaintance" discussion/@comment-432124-20120421180911/@comment-24.131.159.55-20120422044540

About why he did it then--I think it was for two reasons. One, obviously, the entire Team just earned a lot of respect from the League, Superboy included. Two... I imagine the revelation about Red Arrow being a clone was kind of a wake-up call. (I mean, you can't help but feel sorry for the guy.) Superman was probably far enough away from the cloning this time to see what it must be like for the other side, then finally realize, "Oh... I wonder what it must've been like for MY clone?" Given that he knew Superboy's human name, I have a feeling he started talking either to other Leaguers or the Team, and that probably only helped convince him.

(That's what I'm assuming, anyways.)