Doesn't that "unproven personality score hogwash" have something like 9 decades of research behind it and is considered the gold standard of personality testing by textbooks on the psychology of personality?
Mostly the standards of rigour in the field of psychology are deemed flimsy and a lot of findings have failed to replicate.
It's my understanding that Big Five has been replicated consistently across different languages and cultures over the last 90 years and is one of the only things we're fairly sure of in psychology at this point.
The accusation was that it was "unproven hogwash". That doesn't check out.