That was supposed to be a counterargument? Because my every point still stands.
Look, Girl-on-Girl action is VERY popular among hetero men, in some cases even more so than straight. No guys in the scene = nothing extra. "It's like solo girl, BUT BETTER". Cuz, you know, it's not about the fact that it's hetero or homo sex. Hell, some hetero games leave the protagonist out of picture for that exact reason (and sometimes because you can choose your sex as female, like in Hunie Pop; others go for strapon aproach of that, like Lust Affect – but I digress). It's about naked girl(s) doing arousing stuff. And from here I can only repeat the point from before, because it's not a fucking (pun fully intended) rocket (sexual innuendo partially intended) science.