They either make it match or they are fired, illegal or not!
Over the last 50 years i've fired hundreds for a lot of reasons.
I don't have to give them a reason, just hand them a check and tell them to go find a job.
I'm an employee so my decisions are dictated by my boss. The school district here did exactly as you did; employees sued, and their jobs were re-instated. The legal process is ongoing.