We had a management course in the university where this was one of the main things they highlighted:

Managers faults are the managers fault.
Employees faults are the managers fault. Without exception.

And if you think about it, that’s completely true. If an employee does something stupid, it’s most of the time because they a) had the opportunity to do it and b) they weren’t taught well enough. If the employee keeps doing this mistake, the manager is at fault because he allows the employee to do the job where he can make the mistake. He obviously isn’t fit for that position.