Yea that’s what he says in the thread, it’s a negative example.

“Thinking about this while considering the challenges that @UnderdogDevs face in trying to help the previously incarcerated into software jobs.”

Here’s a link to the Underdog Devs organization: https://www.underdogdevs.org/

It isn't that easy to do. Anyone advertising their ex-con status is sabotaging themselves. So what signal do they use for every inbound resume?

So the company can't just trash the resume. After the interview, if things are moving forward, the candidate can inform the hiring manager of the situation. But if the company doesn't do background checks, they don't ask so you don't tell.

Given some of the shenanigans Carmack himself got up to back in the day (including B&E), I'm not sure he's saying it's the right thing to do, only an easy, commonly used and widely considered unobjectionable first-level filter.