Not really getting on why ppl are pissed.
a) It's not real life, it's a manga
b) Not even a reflection of a real life, it got Succubi in it
c) More likely since it's different than irl, it has different mindset, perspectives, culture, etc.
d) Succubi and SA, in theory, should've been a stigma that the succubi have been suffered. Just as much as some POC have been blanketed by stigmas for a long time
e) Most likely, Rinka is gonna be a wingman for Katou. But hell, if the author wants to go the other way, it's a whatever really. It's gonna be a 5/10 but hey, not everything has to be 10/10 or even 8/10.
f) It's a fucking manga ffs. A mere fictional story. If not liking it, there's tons of more stories out there. Who cares...