That's so incredibly reductive, that I'd go ahead and call it plain wrong.

"Caused by a human" is the lowest tier, first base human instinct analysis of any accident, and as such, unless proven otherwise, can be discarded out of hand.

It comes down to: if a human mistake is capable of causing an accident, your system is badly designed because it assumes a part of the system known to be unreliable (a human) is always reliable.

The whole trick is designing systems that are safe despite humans being in the loop. Then you get to benefit from the advantages humans bring over machines without suffering the downsides.