Whether he's just trying to dodge the flak or is sincere (and, to be fair, the apology does sound sincere) I do think Whelan admitting he was in the wrong does set an important precedent, inasmuch as precedents mean a damn thing on teh innernets.
Hopefully, publius' pseudonymartyrdom can serve the greater good.
I think this episode goes a long way toward officially ratifying one of the most important unwritten rules of online ethics, i.e., that a person's decision to write under a pseudonym should be respected barring compelling reasons not to do so. And retaliating against criticism is not such a reason. To the extent that rule is widely understood and acknowledged, it will encourage greater participation in online politics and result in a greater variety of voices being heard.