Are we supposed to laugh at this? Seems like an extreme case of simply not being up to the job or a company hiring idiots instead of professionals to save a few pennies.
You never made a mistake in your life?
These things happen. They shouldn't., but they do. It's fairly safe bet he/she isn't likely to repeat that mistake any time soon.
Much more of an issue is how the company dealt with the incident and communicated it.