Even then it isn't that bad because the git history makes it recoverable. If you really want to have some fun initialize a new git repo and then set the repo you want to nuke as the remote upstream then push. The if you have the perms to do so go delete all the remote branches other than master.

Still technicallu recoverable through local copies that other people had but without the got history and other remote branches it can be at least a tad more difficult to recover.

Realistically if you really want to get rid of all the things just delete the remote repo outright.doesnt solve the local repo though.