Maybe because someone thought they'd be too powerful?
What with the Telepath's high Charisma, and Various feats for boosting Bluff, A low level Telepath can easily make the king believe he (the king) has smoke coming out of his (the king's) posterior, and that he (the king) should retire to make room for one (ie the Telepath) more able.
Make that with regards to Intimidate, and no-one would even dare to approach the Telepath. He'd just glower at them from a distance, and they'd all just kowtow before such a mighty influential being.