I know that part of it is lawyers and police. If you say "I'm sorry," in many contexts, that puts you on the hook, legally. Most lawyers will advise you to keep your mouth shut, and never, ever admit a thing.
I was taught to promptly admit when I'm wrong; regardless of the consequences. Also, to not cop to stuff that I'm not responsible for.
I have often had arguments with (American) people, where they are 100%, without-a-shred-of-doubt, wrong. Often, embarrassingly so, yet, they Will. Not. Admit. It.
I could bring the spirits of Carl Sagan and Stephen Hawking in, to show them they are wrong, and they will still never admit it.
It's actually kind of sad.
My ability to apologize worked extremely well, in the Japanese corporation. They respected it, and I was given a great deal of deference.
On the other hand, the Americans tended to be pretty much dicks about it. If I apologized, they usually tried to use it to gain some leverage, and bully me.
I don't think there's some general "(American) culture of blamelessness," and I think your comment might misunderstand the point of it.
My understanding about "blameless culture" is it's all about avoiding counterproductive things like scapegoating, blame-shifting, defensiveness, etc. Removing those things encourages the full cooperation of the team in resolving the issue, by removing the anxiety of punishment for being the guy who's being blamed. Everyone's supposed to take responsibility.
At the same time, we have made the words "you screwed up" almost a swear in the workplace. If you can normalize "you screwed up" so that everyone hears it (and let's face it, everyone screws up once in a while), those words don't hold nearly as much power. In a sense, the ideals behind giving every child a participation trophy have been extended into the workplace under the guise of avoiding counterproductive things like scapegoating, and I'm pretty convinced that's a bad thing.
I can't. There's no value in it. What did we, as a team, do that allowed the incident to happen? Yes, John Smith shouldn't have dropped the tables on production, obviously, but does he really not know that as part of the incident response that he's (presumably) also dealing with?
If he's truly not aware that was a mistake, there's an underlying transparency issue that goes way beyond telling an individual they screwed up.
"Negligent" doesn't just mean "made a mistake." It means something more like "their carelessness led to a mistake."
That person hearing "you screwed up" will cause significant behavior change. I daresay it will encourage them to make the prod tables very hard to drop, and since they are presumably a smart person, when combined with the postmortem of the incident, it will encourage them to look for and proactively fix similar problems, and generally align the team with good DevOps practices.
It is important in all of this that the right person gets the message. I assume you expect that to not happen, since that is one of the theses of "blameless postmortems."
Ideally a blameless post mortem allows the freedom to identify any of the potential fixes that could've stopped this, and empowers anyone who could've dealt with it to deal with future issues. If you blame the manager then that can implicitly absolve everyone else in the chain.
With that said, I would agree that having a primary owner of things does matter. For that reason, sure, making the manager more aware might help in future. I still think it's a bad idea for org culture though because many managers will respond to "You screwed up." with trying to ensure future blameables find their way to another target. Instead, I'd prefer approaching the manager with "We could've caught this in [any of the ways we could've caught it].", and if the manager doesn't care at that point they're just fully incompetent.
I agree that what you are describing is the ideal, but I don't think it happens often. What I have seen more is that the postmortem turns into 10 different open bugs, 5 of which (usually bandaids that stop that particular failure mode) get closed quickly and the rest of which (often including the real solution) get put off until the next crisis.
Ownership is really important, but hand in hand with ownership is responsibility. That step is missing in many orgs today.
With that said, I think your comment describes kiss-up and corporate fiefdom culture. There are plenty of examples of that. I wonder if non-American cultures are different in that respect.
One very key distinction is freedom to admit error vs "the baby is not ugly." I don't think blameless cultures are the norm, where people volunteer to write post portems and voluntarily submit after action plans..