You’re missing the distinction here between incompetence and malice. One member of leadership acted maliciously; the fact that they were successful indicates that leadership as a whole was missing some controls (formal or otherwise). The latter party is analogous to whichever engineer accidentally brought down prod, whom our post-mortems should not blame—but the former is not.
If some dirtbag got angry about being passed over for a promotion, got offers for a new gig, and then rage-deleted prod at 5pm on their last day, you get to blame that dude at the post-mortem.