Sometimes it's just ...I don't know what to call it, but a kind of humor or private joke between them. They really aren't putting each other down but playing. Other times it is just meanness. You are right though. Women should be respectful (maybe not the best choice of word) to their husbands also. You have to go back to where was this behavior learned though. Little kids learn by example at home.
In the case I described, it's just meanness. She has confided in me that it's been a problem their whole marriage....actually breaking them up for awhile. (their in there mid 50's.) That's what makes it even more uncomfortable for all around. She always looks like she's going to cry...and I think he enjoys hurting her. It's making my husband not like him either. Individually, they're terrific...but together??? Sigh....