This is a truly wonderful article! I have extremely strong fandom beliefs and totally judge other people for being wrong, but I entirely take the point you're making here. This was so well-constructed and educational for me.
One additional point I often consider is if strong beleifs come from socio-cultural issues. For example, I am extremely into Johnlock and Zutara as ships, but they also tie into a lot of personal issues I've had. Queerbaiting, for example, sucks and has really affected my life negatively. I sometimes accuse people of being homophobic or racist because of their ships, but only when I think it's true. (My problem with Kataang, by the way, is that I've been assaulted and I am NOT OKAY with Aang kissing her when she said no and was clearly uncomfortable. Their whole dynamic was way toxic and he literally said he saw her as a mother figure. I'm so tired of needing to parent manchildren in relationships. And also. The assault.)
My rant aside, sometimes people get very fierce because they identify social justice issues in the characters and then get all righteous about it, when I forget routinely that there are shows like Once Upon A Time and Hannibal that are straight up ghastly, but it's fiction and we're supposed to enjoy ourselves and not take everything as if it were happening in real life.