But that's just Morrigan. She's a special exception. Wynne's a mage, and I like her.
The Mages need to be kept under control. Apostates like Morrigan cause all sorts of trouble. It was a Apostate that had poisoned Arl Eamon, Connor's father, and it was that that lead to him being possessed by a demon. No member of the Circle would ever even let the thought pass their mind.