It's taken me a long time to understand this, but sometimes the single mistake is something that leads to a cavalcade of mistakes. That could be putting a burned out person in the review pipeline who greenlights everything, it could be an overzealous engineer trying to make a name for themselves with retention and engagement, etc...

As pointed out earlier, we do need to let people make mistakes, and often their paths will appear to be non-linear. I struggle with this too, but a world that doesn't understand that is much worse.