Do AB have an hierarchy of human error vs system logic? Maybe they do...
Airbus don't, but the
regulators do - because the regulations, and the means we show compliance to those regs, are shaped by past experience. So if a previous form of crew error has caused an accident, then chances are there will be a reg, or an interpretation of a reg, which requires us to design-out that failure.
Whereas a pilot error that I dream up sat at my desk, but which hasn't happened yet, gets dismissed as "there's no way that could happen, and anyway the SOP deals with it" so we don't design it out.
The regs aren't derived from first prinicples; they're the basis of experience, and anything 'new' takes us outside the regulatory comfort zone.
AC621 has made everyone gunshy of inadvertent in-air GS deployment, so we (all) design it out.