Academic freedom may give tenured professors the right not to be fired for what they say and write, but it does not prevent the University from removing them from teaching.
All the more reason for considering at tenure review whether a person is likely to be productive after being give a job guarantee. It is reasonable to ask whether a person will contribute to the goals of the university or will use the job guarantee to pursue activities detrimental to the interests of the university.
Then they should be honest about it and admit it.