I'm not sure a line has to be drawn. It doesn't have to be like real life because it isn't. It must line up with familiar emotions held by human beings, but their actions and reactions do not have to be predictable or even legal. They are the way we speak without fear of anyone calling us on it. Saying that cartoon characters have to conform to what we humans feel is justified, is just beyond my ability to comprehend. It's fantasy in it's purist form, it doesn't have the results that real live action would have and therefore does not need to be anything but entertaining. For example, if Snow White were attempting to fit in with human emotions, wouldn't she have to explain her living with seven dwarfs in a cottage in the woods. Of course, she would, but it is fantasy and even the most ridiculous of story line, we accept it because we know it isn't real. Spiderman, Fonzie, Kermit and any other none live action show (meaning anything with a believable story line) are not bound by rules of human sensibilities. So, why are we trying to make that be a requirement to be good, when it is illogical to even consider it.
The things that you are asking about are live action, with quasi-believable human story lines and therefore are labelled as a human emotion type of entertainment, and bound by behaviors within the norm of real life.