Firing someone for making a mistake, is this a de-motivator?

Would you fire this guy?

A man appears to have deleted his entire company with one mistaken piece of code.

By accidentally telling his computer to delete everything in his servers, hosting provider Marco Marsala has seemingly removed all trace of his company and the websites that he looks after for his customers.
Man accidentally 'deletes his entire company' with one line of bad code | News | Lifestyle | The Independent

That proofs the necessity of a full backup, to media that is easy accessible for reading but not easy erasable.
It can be a tape, or a snapshot filesystem.
Also, there is a need to regularly audit your configuration management. Where this can be something like ansible, or something simple like a cron job.