She's not wrong.
No one's doubting the man is qualified, but phony diploma mills are a dime a dozen. Anyone could print up a homeschool high school diploma.
So you are okay with a local administrator interpreting the wording on the specific document used to advertise the position should be changed to what she THINKS it should read, after the announcement has been published.
What is her rationale for making this distinction? Where is the LEGAL requirement that the diploma be from an accreditted school defined? What law is she citing to make this determination?
I wonder how many of the firefighters, police, other city workers will be affected by her decree.