The neesan is right, both of them are weird but the aniki is definitely the more weirder one here, why? It's because she's the older sister, like if you know your little brother likes you the only right decision is to reject his feelings, their not related by blood and that's what makes her the weirder one, sure gorou is also weird for liking his own big sister but she's even weirder that she knows his feelings and keeps teasing him again and again and to top it all off she's the one who (probably and kind of did) introduced him to the weird perverted stuff he plays and watches.... In conclusion I hate the aniki more than I hate gorou and gorou should end up with mizuno instead of his bitchy no good sister.