Blanket statements like that should be taken with a grain of salt.
F500's are not one thing. You don't have to scratch deeply to find teams running production DB's on k8s (ignoring or accepting the trade-offs, of which there are many including working with vendors and existing DBA's and their solutions) and you'll find DBA's evaluating the same and other trade-offs for themselves.
I personally think that running DB's on multi-tenant k8s with nodes that weren't specifically allocated for it is strapping in for a bad ride.
EDIT: part of actions, codespaces and packages are not run on k8s, but 80% of github services are
That's really not the endorsement you think it is.
For example “users cannot resume code spaces created before the incident” sounds a lot more like an application level problem.