I appreciate your stepping in to tamp down the vindictive comments in the thread, but this post struck me differently than other people.
Wait, what exactly did he do to earn your resentment? According to this description, he just failed to have the courtesy to acknowledge your apology for your mistake. That's a reason to be disappointed, but I don't see why you'd have any resentment to let go of.
It just feels like a mixed message: "X deserves the criticism you're all giving him, and by the way he also deserves criticism for this other thing he did in the past... but let's all take the high road and not criticize him publicly."