Cause HE DOES look like a child, he looks like he just started 3rd grade. We know petite people exist but why did they have to make him look like that? Also its normalize in the manga and even anime industry that once your character is small and literally has a cute face, that is a child. Heck he looks like Ren Kaido from Super Lovers.
it's called representation. just because you're used to one body type, doesn't mean you get to bitch over anything, get over yourself. He wasn't small just because, he was small to highlight their issue which was the seme being huge in all aspects. Also, they are the same age, that's the huge difference with this being a pedo sht like superlovers, hope that helps!
I never talked about this being a pedophile story, what i'm implying is that he looks like Ren because Ren himself is a KID and they look quite similar. We're all different people and sees this story differently, and ofc have opinions differently too. If you see me explaining as bitching then that's on you, i'm only apologizing because you misunderstood my own words and started shitting on me just because i said to you why they're talking shit about his body type.
honestly i don't get everyone saying he looks like a child (an infant even lmao), if you're seeing petite ppl who got a small pp (which exist btw ig yall ignorant af) as children then i think that's your problem lol