You're trying to apply morality to a literal PNG.
I mean, good luck with that, but it's a steep rabbit hole to go down into. Especially concerning characters that basically look like adults. She isn't real, and technically, neither is her age, nor personality. Even on the moral side, people could use their own headcanon to age her up any time they wish to lewd her. The logic here doesn't hold up, lmao.
Not that you really need to age her up. She doesn't even really have an age, because, again,
she's a drawing. Morality goes right out the window when you realize that any traits that a fictional character can have are... (shocker) not real. They're inherently not real, because, again, they're fictional. You can really only make a case for something that is either inherently real or inherently resembles morally dubious material, such as lolita stuff, but that's a whole other can of worms. Uraraka passes all of those criteria, though.
You're effectively arguing for pixels on a screen which is in the same category as people wanting to stab Horikoshi for not wanting to make their favorite ship canon, lol.
And for the record, I think if she were more loliesque, you could make a case here, but in my opinion, outside of that, I think people are just grasping for straws.
And for legal purposes, I am hereby required to state that I do not condone any fixations or possession of any material that is borderline lolita for anything outside of artistic merit.
Anyways, thank you for listening to my TedTalk. Good day to you all.