What made you think that you have a say in who they hire?!
Obviously this could’ve been handled in a much better way, but so many people these days make things their business that isn’t!
Just for the same reason you do not get to decide who, your dentist, barber, grocer, doctor etc. hires, you do not have a say when it comes to school staff.
The fact alone that they were already banned from the school grounds before this happened tells me that they are the problem!