Even after deletion, Wikipedia keeps the history of editions. If Wikipedia's moderators got to remove the edition history as well, it won't suffice, as there are many backups of Wikipedia out there, because Wikipedia itself is open and easily downloadable (just a couple of gigabytes). Also, there are Wayback Machine and Archive Today.

The desperate order to "delete everything" just confirms how managers and CEOs are absolute unaware of how tech and internet actually works.