This is just a wild out of the blue take and olderthannetfic may respond with something sarcastic that I might richly deserve, but I promise it's being presented in good faith.

I think one thing that's going on here, aside of the usual batshittery, is that people have stopped considering fandom as something subversive to the system and have started considering it part of the system. To those of us who grew up in the latter part of the previous century, fandom is deeply subversive, because the system that we grew up with -- the one with all the flaws, and with the embedded corruption and discrimination and what not -- was not aware of it, or when they were aware, they dismissed it as weird at best, perverted or disrespectful at worst. The point of fandom was to look at all those power structures and subvert them. Fandom was transgressive, and therefore transgressions within it--reactions against the mainstream, including mainstream ethics-- are part of the cake. They're a feature, not a bug.

These days, when people grow up around fandom, they consider it part of the system. Artists and companies endorse it, encourage it, try to commercialize it. Everyone knows it exists. So it seems part of the whole monolith of racist, sexist, etc., culture, and therefore, "calling out" pieces of it seems like genuine activism. Rage against the machine. But this ignores the fact that fandom itself is, still, its own rage against the machine. It's a bit like going to the Rocky Horror Picture Show and getting upset that people are shouting things at the screen because you're trying to enjoy the movie. When directing this kind of "callout culture" self-righteousness is wholly appropriate for the actual system, it turns into downright meanness when it's aimed at transgressive, transformative fandom, which was always supposed to encompass the dark side of how we consume and interpret media. One wonders if there is a schism in fandom itself between people who consider it "normal" and those who still see it as a refuge for people challenging mainstream culture. Or if there needs to be better terminology to define those two groups.

I'd assume that a lot of the people reblogging and agreeing with this have probably met bad actors who also shut down discussions of how the original media is racist/sexist etc. with a "this discussion is against fandom etiquette, you're not allowed to be critical on main" sort of thing.

I saw a different post going round about this type of thing where someone had written along the lines of "I'm so glad people are criticising the 'don't talk about racism in fandom, that's not fandom etiquette, fandom is supposed to be fun' point-of-view. We need to talk about how people like me often can never customise a character to look like ourselves. How even if I can change my skin colour, my parents or grandparents will still be white. I shouldn't be getting shut down for being upset that my favourite game doesn't allow me to choose my natural hair as a hairstyle option".

And sure, no-one is obliged to engage critically with their fandom media of choice. But it seems to me there's also a conflation of "Fandom etiquette means don't criticise fanworks" with "Fandom etiquette means don't criticise any media I enjoy", and lots of people are railing against the second one? There seem to be two different arguments going on here at least, but just all using the same words, and that misuse of words is muddying the waters.

I agree that there's two different arguments happening here, because what you're talking about is not criticism of racism in fandom, but criticism of the media that fandom is based on. If you're playing a game and you make a character who's Black but their relatives in the game are white, that's genuinely a system problem. That is racism in the system. It is not racism in fandom. Just because a work has a fandom does not mean the work is the fandom.

THE MEDIA IS THE SYSTEM.

THE FANDOM BASED ON THE MEDIA IS NOT.

There should always be criticism of the original media, that's absolutely fair game and is often the subject of fandom discussion. Absolutely 100% agree with you.

But when the criticism turns to fanworks - and again, fanworks are not the system, they are not media, they are transgressive and transformative OF that media -- then you are doing the thing where you tell the people at Rocky Horror to shut up so you can enjoy the movie. When you say "this fanfic author is racist for writing an interracial relationship when there's another Black character you could pair the main character with." (This has happened to me.) When you say "This person should rewrite their fic because they wrote an asexual character with no sex drive, and that's a stereotype." (This has also happened to me). You are missing the point that these works are responding to the system. They're imagining possibilities outside the scope of what the system allows. Each one of them adds a layer to the multifaceted cake that is reinterpreting and reimagining the source material. No single fanwork has the responsibility of being the whole cake.