I have a whole tag on this, actually–Conservative Christianity In A Gay Hat–because I’ve been watching from the sidelines, growing increasingly disgusted, for the last two years. So… this got a bit elaborate, and I’ll try to put a TL;DR at the end :)
I’m cismale, and I’ve been apologized to by an anti that targeted me on the assumption that I was a woman. But I’ve only gotten harassed a handful of times. Meanwhile, my AFAB and queer fandom friends get harassed nearly continuously for daring to write darkfic, for writing queer fic, etc. And having lived through Strikethrough ‘07 myself, the rhetoric that is used by ostensibly progressive antis is literally indistinguishable from what Warriors For Innocence used back then.
Summarizing in broad strokes, there are a number of factors at play here, because Antis are a predominantly Tumblr-specific social movement.
You have Tumblr’s Web 2.0 design, which pushes outrage, polarization, and misunderstanding through various avenues (undated and out-of-context posts reblogged where the OP might have apologized or been misunderstood, to give one example). It’s also a non-delineated, unmoderated, amorphous space, without any form of barriers between public activism and private entertainment, which blurs the line between the two and causing conflation between them. For an example of that, I’ve recently seen a whole Discourse on “Anne Frank as bisexual representation!” being excitedly discussed by non-Jewish people, as if she was a character in a fictional work, and not a living breathing child who died in a concentration camp.
As a sub-part of Tumblr’s activism culture, it is worth pointing out that that culture itself is inherently performative, as opposed to substantive. While many people are activists offline, and Tumblr is good for raising awareness of issues, in the social space, there is that competition for “Wokeness” as part of the social environment, not the activist goal.
On top of that, a large number of the people on here are already marginalized socially and politically, lacking influence and power and institutional control over their own lives, being POC, LGBT, or something else that is actively Not Heterosexual White Christian Cismale Capitalist. So there’s an impulse to want to assert control over what spaces you have power over, even if that control is ultimately destructive.
Furthermore, Southern Baptist-style Evangelical Christianity has grown in cultural influence over the last generation in the US, as the US’s culture has taken an extreme rightward shift after 9/11. And American Christianity in general, and Southern Baptism in particular, have a fixation on the sexual as uniquely sinful, and this has bled massively into the overlying culture. (I moved to Germany just over two years ago, and there was one culture shock moment that I particularly recall; I was in the grocery store before New Years with my then-fiancee, now spouse, and walked past a calendar display–and nearly gave myself whiplash. Because there were the Playboy and Playgirl nude calendars, right there… where the children could see them! *exaggerated gasp* Mind you, the four-year-old walking past with his parents didn’t seem traumatized, but imagine the reaction if that was on the calendar display in any US grocery store). And while many antis do not identify as Christians, that anti-sex acculturation is still there, along with the rest of the various cultural baggage that comes with Conservative Christianity.
So mix that all together and you have:
A marginalized group of disenfranchised people
…who have been brought up in this extremely puritanical mindset
–A mindset that is happy to censor expressions of AFAB sexuality in particular
Which is operating in a social space that conflates actual activism with performative actions
…as part of those performative actions, target the people they can reach, because they can assert control over them.
…Does not understand the difference between public activism and private entertainment, much less the niche that fandom operates in, and the impulses towards shipping wars has not gone away
And sees, in this amorphous space, the production of media that they dislike and that does not meet their standards for sexual purity.
So what started as “I don’t like this ship” turned into a “this ship is disgusting” turned into “you’re a sexual deviant for writing it and I’m going to Call You Out For It!”
Because they fell back on the rhetoric and mindsets that they were acculturated with–AFAB sexuality is bad and should not be expressed or explored, and there’s no delineated private space in which to engage in that exploration (except AO3, which is why Antis hate it). And since they’re operating in the Tumblr sphere of “wokeness”, they reach for the tools they know, the language of progressivism and performative bullying, in order to dress up and rationalize that reactionary agenda.
Yes, it it totally Southern Baptist Rhetoric about How Sex Is Uniquely Sinful and Sexual Purity is the Most Important Thing, dressed up in progressive clothes for the visit to Church Tumblr Wokeness, having snuck in through shipping wars and wanting to censor AFAB sexual exploration and expression, with the same target list.
Much like how most New Atheists (the “Rational” racist fedora-wearing misogynists) are so busy rejecting Jesus as their Personal Savior without bothering to examine the rest of the cultural baggage that comes with their upbringing and thereby conflating all other religions with the specific flavor of Christianity that they’re rebelling against, Tumblr antis are also so busy Trying To Be The Most Woke and forcibly censor the production of content they find objectionable that they aren’t examining the cultural origins of what they find objectionable. Because while black-and-white good-and-bad mindsets don’t map to the grayness of the real world very easily, they are very simply and energy-efficient for the possessor. (And this is why I say “Be Careful Who Defines Your ‘Good’”)
(P.S. I know that a lot of this is familiar to you, @vaspider, due to you experiencing the same policing in a different context, but I figured that laying it all out as one piece would be best for general clarity).