Dear Steve, Heather and anyone else that fits the bill
It's okay. People sometimes say hurtful things despite historically having strong opinions about never belittling other people publicly. It doesn't mean that they truly mean it, and it doesn't mean that you should take these negative things to heart either. People slip up because we're multifaceted creatures and despite our intentions to be the best person all the time, well that's just not possible.
Regardless of whether what you're being criticized for is justified or not, it is inevitable if it's been made public. The irony in this case is that the bully is being made feel worse because of his past blog posts, which is also sad but just as inevitable. It's okay Steve, we all fuck up, and the ease of doing it on Twitter doesn't help.
Heather, I promise you that any decent potential employer is still exactly that. Nobody will disqualify you from a job position based on something you've made. You've open-sourced it, so if anything you get bonus points. You will always be criticized, the trick is to ignore the haters and know that people in a situation of genuine critique (i.e. candidate interviewer) will never judge you (as badly) as some people on Twitter did.
Do not let this discourage you from contributing publicly in future either, even if your code IS shit. Everyone's code is shit, at least to some people. As long as you're happy with it, that's all that matters. Also, somewhere down the line you'll look back at it and think "Wow, that's shit code", which just means you've gotten so much better.