We love our mommies, but sometimes don't we expect a little too much from them?
GRRM on Cat's treatment of Jon: ""Mistreatment" is a loaded word. Did Catelyn beat Jon bloody? No. Did she distance herself from him? Yes. Did she verbally abuse and attack him? No. (The instance in Bran's bedroom was obviously a very special case). But I am sure she was very protective of the rights of her own children, and in that sense always drew the line sharply between bastard and trueborn where issues like seating on the high table for the king's visit were at issue.
And Jon surely knew that she would have preferred to have him elsewhere."