I think the fact that so many people want to label Leon/Ashley as canonically "sibling- coded" is because they feel threatened in the way they view other of Leon's relationships, they can tell Leon and Ashley have chemistry and they try to convince themselves that they have a familial bond going on (like Ellie/Joel) so that they can justify not shipping them and making people who ship it feel bad/weird.
Because nowadays so many people can't just dislike something, they have to make up a reason why it's morally wrong and unacceptable so that way they can bully people that think differently and feel like their own personal opinions are objective and right while everyone else is wrong smh. This is mostly the case with younger fans (tho a lot of people older than me does this too lmao) so that's why I don't really find it frustrating bc it's most likely they have limited real life experience. Plus they might not be that good at interpreting canon from contextual clues yet.
In my case though I think a lot of these people are actually doing the opposite tbh because to me it just shows that they recognize that Ashley's relationship with Leon is real and they can't even concede that they're friends in the canon because they know it could lead to something else if followed through in the story, they admit there's potential there subconsciously with how hard they try to make it seem otherwise with nonsense claims. It's like when insecure guys feel uncomfortable but try to seem tough by buying big trucks and having guns on them all the time lmao.
So, I've talked about this before -- about how the "sibling coded" or "problematic age gap" discourse is just modern-day fandom's way of slutshaming and engaging in casual misogyny in a societally acceptable way.
I'm pretty confident in saying that anyone in my generation who slaps "siblings" on Leon and Ashley are probably people who have another ship and have had it for a while and don't want Ashley getting in the way of it, tbh LMAO
Like.... my generation has co-opted the current generation's vernacular, but make no mistake about the kind of bitches we are. We're ship war bitches. That's all we've ever been AND WE ARE NOT GOING TO CHANGE OUR WAYS NOW fjdskfh
But if we're talking about the current generation...
Media illiteracy is a big factor in this. It's no secret to anyone that the US education system took a massive shit starting in the late aughts/early 2010s, and things like critical reading skills aren't being taught in schools anymore.
I graduated high school in 2007. Two years later, I went back to visit an old English teacher to get a letter of recommendation, and he was lamenting to me that he'd just given up. It wasn't worth trying to explain the deeper themes of Beowulf to kids who didn't care, because the only thing that mattered was getting them to pass standardized tests.
So, now, without an overt, explicit declaration of love or something visually concrete like a kiss, kids literally do not have the skills to parse through a text and pick out themes and tropes and use of symbolism and imagery. They were never taught how to do it.
But there's a more culture-based thing happening here, I think. It's this fucking mess of a cocktail of internalized misogyny paired with learned helplessness, social anxiety, intense sheltering possibly exacerbated by the pandemic shutdowns, peer pressure, and internet purity culture.
I think it's pretty safe to say that fandom is predominantly made up of women and teenage girls. That was true in the 60s in Star Trek fandom, it was true in my generation, and it's still true today. And what I've seen happening today is that young women are absolutely terrified of their own sexual agency -- because the internet keeps telling them that, if you're under 18, it is wrong and bad and unacceptable for you to engage with anything even remotely sexual and how dare you express your sexuality -- and you'd better not do it not just because it's wrong and bad, but also because you are GUARANTEED TO BE PREYED UPON IF YOU DO. SEX IS DANGEROUS ALL OF THE TIME AND YOU'RE LITERALLY TOO YOUNG AND TOO STUPID TO UNDERSTAND ANYTHING SO DON'T TRY TO EVEN THINK ABOUT IT. Because if you're 17 and he's 18, he's a pedophile!!!!!!!!
So, we've now basically turned an entire generation of young women into the same type of young women who created the BL genre in Japan. These are women who were too afraid to explore their sexuality on their own, and it felt safer to do it with two male characters, because it was always more "okay" for men to be sexual. This is happening here in the West, now.
Slash ships have always been a thing in the West, but not to the degree that they are today. In today's fandom, if you have an M/F ship at all, you are outnumbered by at least 3:1 -- because M/M just "feels" safer for a lot of the current generation.
So, I think young women look at the Remake portrayal of Ashley Graham, and they identify with her. A lot. They're probably around her age, and her personality is very relatable to the kind of girls who play video games. Ashley's clearly introverted, but she's a fast learner who just wants to help, and she's got a good heart and a weird, kind of awkward sense of humor.
And, not only do these girls identify with Ashley, they're probably thirsty as fuck for Leon.
But that's terrifying to them.
Because they have been taught to fear their own sexual agency. The idea that an attractive, traditionally masculine, older man would be romantically or sexually interested in them is immediately categorized in their brains as wrong and bad -- and they don't want to think of Leon in that way.
So... for them, it can't be romantic. It can't be sexual. But there's clearly something there, but Leon would never abuse or prey on anyone so... that bond must be a perfectly innocent familial affection. That's what it is. That's what it has to be, because anything else forces them to face the uncomfortable reality even young women like them go on dates and have sex -- and sometimes, it's with men like Leon.
So, they thirst over Leon at a safe distance through Luis, primarily. Or they self-indulge on reader fic, because that's so much easier to write off as "just a fantasy" and not a statement on who Leon actually is as a character.
And it's just kind of sad, man. It sucks to see this happen to an entire generation of young women.
That's why I don't really get mad when I see the "siblings" shit out in the wild. I just feel sad for those people -- because they can't just say "I don't like the ship." They're so insecure and neurotic that they have to think of a reason why the ship is literally impossible to ever happen so that they don't have to be worried about it.
One day, they'll finally suck a dick for themselves and learn that it's not that serious. It's really fuckin not. Dicks are stupid, and the boys that are attached to them are even dumber.