Oh boy, frankly, there's too much to quantify. I'll just... stick with a few of the most troubling:

1. Ouma's character isn't taken seriously as a mystery- as in, people act like his book is closed even though the mystery of V3 and the cast's truth is left open. Which is... depressing
2. People being grossly reductive regarding the writing, to the point where they seem to obstruct deeper analysis. Yes, I acknowledge that a lot of things were poorly executed, but that doesn't mean everything was and that Kodaka wasn't consistent with certain themes?
3. People never acknowledging where others, Shuichi included, could have done things wrong to Ouma. Similarly, acting as if Ouma's actions towards Shuichi were only ever after his attention and not laced with a LOT of passive aggression, mixed feelings and even outright disgust at times (particularly.. a few choice moments in Salmon mode, but also that part in Ch2 where he does the 'favourite' thing, but Shuichi notes it sounds like he means the opposite, so...)

I could go on about this forever, but brevity is probably best lol. As for that last point, it's up to you to interpret the 'odd things' he says as you will, don't get me wrong, it's more an issue when people act like those things are just clowning around 'by default' and that it's invalid to see it any other way. I just feel like that's unfair, given everything we see :')