If you "admit where you went wrong" you open yourself up to legal redress, sued for damages, etc. Reputations are also ruined, people do/should lose their jobs, pension, perks etc..
Far simpler for those at the top to deflect attention, blame someone else, invent a false narrative, do a bit of gas lighting - and I'm not just talking about the Chinook here (post office scandal just a recent example), it's widespread.