They said "It's not possible to install a local account any more.".
I'm sure you can understand why my own memories of just recently doing the apparently impossible thing will hold more weight -- to me at least -- than a comment saying the thing I just did is impossible.
That might not be super convincing to an outside reader, but for me the alternative is to conclude that I'm having a multi-day hallucination.
It'd be hard for me to pretend like the anecdotal evidence is equal in this situation.