Link to the archived version of the article in question.
I actually like the editor's note. Instead of naming-and-shaming the author (Benj Edwards), it's blaming "Ars Technica". It also claims they looked for further issues. It sounds surprisingly sincere for corporate apology.
Blaming AT as a whole is important because it acknowledges Edwards wasn't the only one fucking it up. Whatever a journalist submits needs to be reviewed by at least a second person, exactly for this reason: to catch up dumb mistakes. Either this system is not in place or not working properly.
I do think Edwards is to blame but I wouldn't go so far as saying he should be fired, unless he has a backstory of doing this sort of dumb shit. (AFAIK he doesn't.) "People should be responsible for their tool usage" is not the same as "every infraction deserves capital punishment"; sometimes scolding is enough. I think @totally_human_emdash_user@piefed.blahaj.zone's comment was spot on in this regard: he should've taken sick time off, but this would have cost him vacation time, and even being forced to make this choice is a systemic problem. So ultimately it falls on his employer (AT) again.