My daughter started commenting on people's appearance around age 5+ because she learned it from Peppa Pig. Everyone always talks down to and about the Daddy pig constantly. They try to incorporate some 'good' behaviors in the story but certain 'it's just a joke' jokes end up leaving more impressions on the kid than the shoehorned moral of the story. It took us a while to teach her how it can hurt others if you comment on things (even if they are technically factual statements). On the other hand, she learned some simple but useful things from Bluey that we weren't successful in teaching effectively. e.g. She learned to speak up and tell when Dad(me) was overdoing 'fun' things (literally an episode with exact same concept where Bingo has to tell her dad the same thing). She learned to be compliment and acknowledge many things verbally (instead of saying 'why do I need to say it, they know it already').