Either
a) there's a plot hole large enough to drive a thousand Futa cocks through
b) Elli's going to be fucking the entire town.
90% of the people living here are Futas.
You see, the sex drive of a Futanari is much higher in comparison to that of a Man.
And though difficult, most of the time we can sort it out ourselves.
But if there's ever any women around, then things change...
Our libido becomes totally uncontrollable, Unable to be sated by anything other than a woman
90 percent of the people living here are Futas.
Like I said, Elli is the only woman around, And if you're going to be dating her, then she'll be around me even more..
So, all your classmates are in the same boat, and your teachers, all of them have been and will be around Elli even more than the MC's mother is. If Camilla wasn't sexually bent before Elli was born, living under the same roof with her would likely bring out all the perversions, and make her jealously tease the one boy in the village that has Elli's affection.
Every Futa who interacts with Elli on any regular basis is apparently going to need Elli to relieve their sexual desires.
Yet, it is the MC's intimate acts that ease Zoe's needs, not Elli's, and Zoe's complaint is that she's not supposed to masturbate rather than Elli's presence, which make me wonder if at some point we're going to find out that those quotes are bull and just a story Julia and Camilla used to cuckold the MC.
I wouldn't be surprised about Camilla doing that. It would be very fitting for Camilla's character as written so far. It would be very wrong for Julia's character as written so far.