Another thing that might be helpful is if people who actually know the people involved in this decision, e.g. the head of the department, will write to them a private email expressing their disappointment from the decision. The same might be true if prominent mathematicians will do so.

I am not suggesting in any way to harass them, but to try to start a dialogue and to explain how bad this looks from the outside. People are more likely to listen to people they actually know.