I don’t want every poly character in every TV show or movie to be a perfect paragon of sensitivity and high-minded ethics. I’m okay with them being flawed and human. The need for role models isn’t a need for one perfect hero: it’s a need to see that you have options, other than the ones your culture is unfairly slotting you into. (Not to mention the need for the rest of the world to see that as well.) I don’t think every producer of pop culture has an obligation to single-handedly fill that entire gaping hole. And again, I don’t want propaganda. Propaganda is boring.
But given that there are so few poly characters in pop culture, and even fewer who don’t fall into the stereotype of unethical seducers and skanks with no self-control, I think producers of pop culture do have an obligation to not actively perpetuate that stereotype.