The Bureaucratic University

Almost all universities and even some colleges are traditional bureaucracies. As such:

1. Rules and regulations ensure fairness, in so far as that is a criterion.
2. There is likely to be at least some appointments that are big mistakes, whether because information was lacking, or because someone turns out not to be productive, or because some boss decided that they wanted X and pushed the appointment through. (Most such bosses are insufficiently careful in their pushing, and were the details of the appointment to come to light it would not look good. Typically there is a false search, and sometimes no candidates other than the planned one are invited. Some bosses are scrupulous and there are no fingerprints, but usually pride goeth before the fall.)  In the latter cases, since the bosses have temporary appointments of 3-10 years (chair, dean), there seem to be no clawbacks, and the persons who suffer are the colleagues in the unit and of course the students.
3. The trick here is to sideline X, to find a role for X where they might well be useful or at least do less harm. Even better is to find another institution that needs just what X really offers, and see if you can recommend X for the position.
4. If you find yourself in in the grips of X, it's best  to never respond to them, but be obsequiously pleasant if you meet them. No need to talk about them behind their backs. They always bury themselves.

The alternative to a bureaucracy is a patronage system: you are Mr. Big's "boy" or "girl," and Mr. Big builds an empire around himself.