That's what happens when 'forum police' decide that a post has drifted off-topic, despite how relevant it might be; they complicate things by twisting their panties around it in hopes of choking off conversations they don't like.
It's a relatively simple question and an even simpler answer. In real life, certain guys can't get laid. In real life, pretty much EVERY girl can get laid if she's willing to lower her standards far enough. (unless you are planning on redefining terminology, which accomplishes nothing except inflating your sense of self-importance.)
Thus, the market for 'sexy books' is predominantly male, unless you are specifically marketing the 'romance' genre (which is generally straight and has a set audience), the answer to the question is "Your audience is incredibly small because of your genre choice". Everything else is just politics, and you can't increase your market unless you are willing to pay a lot of money for marketing... That won't increase your target audience, but it is a lot more likely to saturate it.
So a 'yuri harem' is simply never going to do as well, assuming the same level of marketing, as normal haremlit or traditional romance. neither will d*ckgirls, gay, lesbian, or other 'self-limiting' sexual genre choices. This is not a social decision, indictment, or judgment call; it is simply the reality and recognition of the market.
