Because that is where they drew the line for morality. True kids knew and adults knew that these people on tv were not married in real life but two people in the same bed was where they drew the line. Couples back then didn’t really kiss either. Most tv shows had them kissing each other on the cheek. Later a quick peck on the lips was ok for tv, but they took into account that tv was usually a family event. They had to keep things rated G at all times. Remember, when Elvis came out shaking his hips, that was probably rated R back then. Today it his movies would be rated G. Just a little over 100 years ago,women were not allowed to show their legs in public.