How is Azure still having faults that affect multiple regions? Clearly their region definition is bollocks.

All 3 hyperscalers have vulnerabilities in their control planes: they're either single point of failure like AWS with us-east-1, or global meaning that a faulty release can take it down entirely; and take AZ resilience to mean that existing compute will continue to work as before, but allocation of new resources might fail in multi-AZ or multi-region ways.

It means that any service designed to survive a control plane outage must statically allocate its compute resources and have enough slack that it never relies on auto scaling. True for AWS/GCP/Azure.