I really appreciate that this is the moral of your story here. We all make mistakes and engage in behaviors we regret... but it's difficult to watch someone not demonstrating that they're learning from their audience and making efforts to make amends publicly.

It's one thing to send a private apology; it's much more difficult to turn to your audience in full accountability and say "Dang, I really screwed that one up, I am so sorry. Thank you for taking the time to educate me."