Something I think is really important to remember when doing fandom analysis (and literary criticism in general, since it was a litcrit movement that opened my eyes to this), is "You can only analyze the text that exists."
"But the creator was pressured into changing their vision for the worse!" Sometimes this is wishful thinking. Sometimes it is demonstrably true. Sometimes it's ambiguous. If there are documented issues affecting the production of a work of art, you can and should absolutely talk about those as part of your analysis! But 'the creator's vision' isn't real. The version that was actually made and actually exists is. Once I commented that I disliked how an asexual character had been handled in a book, and the person I was talking to said, "Oh, I bet it's their editor's fault." But even if that were true . . . the book is published. I was responding to the portrayal in the published book. I can't analyze a text based on what the other person in the conversation imagined the author's intent might have been. Even when we know for sure that a story would have been very different without certain pressures (an editor who nixed an author's original ending, an executive producer who vetoed all mentions of queer characters, a show that was cancelled prematurely and had to wrap up its plot in a couple of episodes instead of another full season), we can talk about those pressures and we can talk about things we know were cut and we can talk about how the bad pacing of those final episodes were significantly influenced by the circumstances under which they were made. But we can't talk about the platonic ideal of the piece of media, the version that would have existed if the circumstances were perfect, because it's not real. Every person is going to have their own idea on how it would have turned out and these will be wildly divergent from person to person. It's not helpful or productive to get mad at people for criticizing or otherwise engaging with the actual piece of art instead of the version you made up in your head.
"But I understand this character better than the author! They would never have done X!" Look, we've all been there. Do whatever you want with your own personal interpretation. But it's just that: an interpretation. The character isn't real, and there isn't a secret better version of the text waiting to be freed from the tyranny of the person who's actually writing it. You can write an AU, or talk about how, for example, a character in an episodic TV show with many different writers suffers from a lack of consistent characterization, or make a post about how you think X plot point was badly handled or poorly written. And you can absolutely give the character the storylines and development that you want them to have! In this case, you're creating your own text, and it exists, and it can be analyzed either on its own or in relation to the source material. But you can't expect everyone to agree with you, and you can't believe that your interpretation of a character is more real than anyone else's—and especially not that it's more real than how the character is actually written in the text. I see this very often with people who want their favorite characters to be more progressive than they are. Yes, maybe the author's sexism is part of why this character acted sexist. But if you are rejecting part of the text you are rejecting part of the text. Other people will choose not to do this, and you can't blame them for analyzing a character or society as they are actually presented.
For people who really love fiction, it's very easy to fall into magical thinking. The stories and characters feel real, like they exist somewhere out there in their true, uncorrupted form, unsullied by authorial bias and executive meddling and the long, messy, awkward process of actually making and sharing a creative work. But they don't. A piece of art is a material object, a series of words or sounds or images or bits of data that has been put into its current form by one or more human beings. That is what's real. Personal interpretations can be wonderful, transformative works and alternative readings can be powerful and illuminating. But you can't analyze a hypothetical the same way you can something concrete. You can't be so caught up in your own feelings that you forget that other interpretations are possible. And you can only do textual analysis on a text that actually exists.
