Accuracy of that statement aside, that's your argument right there. That shit is one fetish. It should have one thread each.
Also, it should not just intrude on other fetishes.
This isn't about futashit specifically, that goes for all fetishes. I've launched into a full blown Kirk dressing down the monster of the week speech to an idiot who shat up a robot girl thread by crudely slapping seam lines on his fatty porn.
Aside from that, futa gets specifically egregious for two reasons:
It's kind of popular so there are many fags trying spread their gay shit
It's exceedingly disgusting for everyone not into that, cause showing the wrong genitalia is pretty much the strongest way for pron to go wrong.
TLDR: Futafags should have exactly one thread and not a single futa should exist outside that thread.
Also have a pic so this isn't just a wasted bump.