The whole thing just screams of Herdman. Not just doing it, but formalizing and systematizing it. And he was the architect of the women's program for close to a decade then spent several years doing the same on with the men. Priestman is one of his alcolytes, as are most of the senior people with both national teams and technical staff.
And they all knew it was wrong and kept on doing it even after he left.
The low level people might be able to get away with saying their boss made them do it, but there are layers of senior people who knew, knew it was wrong, and kept on doing it, and they all need to go