>As for no more dwelling on past decisions, that is the same thing as Intel's cultural value of "Disagree, but then commit."

You mean the company who is flailing in the market, losing employees and generally considered a bad place to work?

>"See, I told it wouldn't work" is about the most immature and unhelpful attitude to have - no matter how correct it may be.

Blame free post mortems are vital for an organization to grow and improve with time. If you cannot review past bad decisions and learn from then then you will be forced to repeat the same mistakes while your competitors evolve.

>but it undermines everything if someone keeps harping on a prior decision.

If accepting a mistake was made and then publicly coming up with a plan to not have it happen again undermines your ability to lead then you are a horrible leader.