Umar was not rude in his tweets and normal bashing is fine but going so personal when you are not even a part of the show? If she can say all that on national television when she knows a zillion people are watching and it can affect him and his career negatively then he has all the right to call her out and defend himself if he wants.
Also, for those questioning his doctoral degree I don't understand why is it anyone's concern if he has a current valid license or if he is working as a doc or not...it's his choice. He is in a reality show and as far as I remember he did not sign away his rights to make personal decisions for himself. It's his damn choice if he wants to be an actor, model, doctor, teacher, lawyer, business man whatever the hell he wants to be. It does not affect his ability to be a good contestant on BB.