I'm honestly not that surprised that F1nn gets hit on by a lot of straight women. There's a significant proportion of straight women, who only tend to be vocal during their yaoi/fujoshi/BL reading teen phase but then to go silent during adulthood for fear of judgment, who've both A: Often wished they themselves had a penis, and B: Are very into the thought of male/male pairings, both romantically and sexually. It's the equivalent of the old trope of guys who are really into watching lesbians, only with more social shame attached (making it harder to openly admit/discuss). From my observations at least, this population actually seems to be really into prettier guys (making F1nn an ideal candidate). I suspect because on the surface a relationship with a prettier, less classically (and perhaps toxically) masculine guy would seem to provide more flexibility for exploration and power sharing. In our society, there's still a social expectation that women will be sexually submissive and men will be sexually dominant, to the point where you risk being shamed for violating these norms (with both dominant women and submissive men facing that risk), and risk being seen as less womanly or manly (as the case may be) as a result, to the point where even many bi women will identify as being dominant only with other women but still submissive with men. It's why, even though a roughly 50/50 split for dominance/submission should be expected for both genders (as there is no biological motivator towards either), we still see the numbers in our society skewed towards far more sexually submissive women and far more sexually dominant men. For a lot of people, fear of the stigma drives them to the more socially acceptable place, and keeps them there. With a guy like F1nn, there's little expectation of having to conform to such social stereotypes. It gives a bottled-up straight woman the chance to more greatly explore shifting power dynamics without fear of judgment, the opportunity to try out something much closer to the male role from one of their fantasies. It's part of why material written by gay men for gay men tends to have far more classically masculine characters, whereas a lot of BL and shounen ai (which is primarily written by women) feature male characters who are both more likely to be bishonen (pretty boys) and more likely to be more open to their feminine sides.