Blameless reporting is an important ingredient in creating a culture of psychological safety. People need to feel comfortable sharing ideas for ways for their teams to improve without being punished for past suboptimal behavior.
If mistakes are due to process shortcoming, leaders should work to correct these behaviors without addressing people individually. Blameless reporting doesn't mean that there aren't consequences; it means that an organization's culture is focused on finding solutions and learning rather than on finding culprits.
But, blameless reporting has its limits. While it's generally more important to work on constructive solutions than going on witch hunts, suspending blame is only reasonable for honest mistakes. For example, if someone has an ethical shortcoming or is blatantly incompetent, there should be no tolerance. In these cases, it's appropriate to fire people and to distance an organization from their transgressions.