User blog comment:Jessica 'juicy' May/Morgana always bad/@comment-4623180-20120130062323/@comment-5036924-20120202164555

"did terrible things to people with magic. Arthur did too" - perhaps, but she also saw that Arthur did these things with great reluctance. AND he utterly defied his father on several occasions, doing what she and he both knew to be right. He listened to her, did as she asked and generally made far better choices than his father - which Morgana surely cannot simply ignore.

I doubt she suspects Arthur of being behind poisoning her since there was no explicit reference (e.g when talking to Morgause) whereas there are several mentions of her anger at Merlin betraying her. Additionally, she's known Arthur far longer and more intimately than Merlin, and probably is fully aware that he'd always have given anything to save her life. I'm not sure she ever really thinks, deep down, that Arthur would harm her.

Therefore I will have to assume it was the brainwashing that did it. It's really the only feasible thing I can see that would explain such a change in heart.