I love the idea of the blameless retrospective. What's not to like? Getting all the members of a team together to blamelessly review work done at the end of a production cycle or in response to a crisis is a great idea. There's a great benefit in having a fearless, uninhibited, blame-free examination of a problem in order to improve. You get more information and you get better ideas. Every company should do it. The problem is that most don't. Why? Because many, if not most, corporations are, by nature, blame-seeking.
Blame-seeking in corporations is nothing new. It's the low-hanging fruit in cause analysis. Identifying a single point of failure or particular human shortcoming is usually a lot easier than doing the complex work required to really understand why a failure occurred. However, this is not to say that placing blame and taking actions based on that blame assignment is an ineffective way to address an issue. Sometimes it's justified.