It doesn't make him a villain, but simply a shitty person and bad older brother 💁♂️
yeah, I'm just gonna be blunt, and call that bullshit.
Per your "prove me wrong list" in your other comment, go back and read chapters 9-12, 22, 25, 38, 31, and 36.
Everything Reiya is as a person & character is because Youta has looked up to and idolized him since they were young children. Youta sees Reiya as his inspiration and someone to strive to be like, and he would constantly compete with Reiya in everything no matter how often Reiya beat him. And Reiya pushed himself harder and harder in every facet of his life and adolescence in order to continue trying to be "a cool older brother", because he wanted to keep being someone that Youta looked up to.
In the process, Reiya started to take "being perfect" too seriously, but because he worked so hard to impress Youta, he started getting attention from everyone around them who had no awareness or understanding of
why Reiya was pushing himself. He started getting accolades, praise, and that snowballed into him putting more pressure on himself, striving to never let that "mask" of his slip until he was trapped in it. The one time he didn't do something perfectly, he was called out by a peer, and that terrified him—he was locked into needing to never show weakness or imperfection, and thus "Prince Reiya" was born.
Simultaneously, Youta started to get demoralized by being "forgotten" by all the random people around them who would praise Reiya at every turn.
Importantly, he never voiced this aloud to Reiya, or to their parents. He carried that frustration internally, and he
also never took it out on Reiya or blamed him. He simply stopped trying so hard and stopped trying to compete against Reiya as he always had, but he never voiced the reason why, and otherwise acted normally around Reiya and their parents in the day-to-day.
That's important; he didn't turn "cold" toward his brother, he didn't pull away or stop interacting with them. Reiya noticed that Youta stopped competing against him so much, but because he was so preoccupied trying to maintain his visage,
and because Youta still treated him the same outside of school when it was just them as family members
and still looked up to him, it was chalked up to Youta being a teenager and having things going on that weren't to be pried into. Plus, Japan's pretty big as a culture about not sticking your nose into other peoples' business without being invited, and that's an important thing to remember for this specific context. Reiya giving Youta space, especially when they were otherwise the same as always, isn't out of the ordinary whatsoever.
But the moment Youta met Houjou and started changing, Reiya noticed, as early as the sports festival arc when Youta races against him. And Reiya makes a point about how he'll never "go easy" on Youta, because if he did Youta would actually beat him—Reiya very much acknowledges how good Youta is inherently, and he constantly pushes himself because he doesn't want to "fail" Youta's expectations. And Youta understands this: he doesn't resent Reiya, or hate him, or see him as a bad brother or a bad person. Reiya's still his idol and inspiration and his big brother, and nothing about their relationship is ruined by Youta's hangups or his trauma regarding the girls around them.
But this whole "Reiya's a shitty person and shitty brother" is absolutely unfounded. He's caught up in his own nonsense, but he's never simply turned a blind eye to Youta. It's why he notices Youta changing before he ever officially meets Houjou, and why he goes and follows Youta to the part time job, and asks Youta to accompany him shopping, and why he asks Youta to help out at the festival food stall. He's actually a pretty big BroCon in his own right, and he was more sad than anything that Youta pulled back and stopped chasing after him as he used to, but didn't pry into that business because...it's Japan, and he trusted Youta to come to him if something was
really actually wrong.
You're free to your opinions, just know that they're the result of a poor reading of the series and the characterization as presented by the author, and I would suggest not being surprised when people call you out on it.
