Maybe. To one extent kids seem to think this way when they are very young. They are just innocent. So a show where no one is really bad is going to appeal to their preconceived notions of the world. Which means more of them watch. Which means more success.
At the same time the data on human happiness is there. You really are going to be a happier healthier longer lived person if you have a big social network of people who love you. Given that in the modern world no one really is stuck with anyone and relationships are by choice your best self interested way to live is to be kind and generous. And what kind of monster wouldn’t teach the best way to live to children?
Now you are free to be miserable angry loner. That is your choice as well.