Don't worry, I'll do it for you.

One of the reasons this is so prevalent in the 1x1 section is because some of those RPs tend to be more... personal, than group RPs. For some people, it makes them feel awkward to engage in "romantic" acts with a character that is not being played by a genuine member of that sex. I think we've all seen a story involving a super hot/cute girl avatar seducing men and it turns out to be some ugly dude. Learning to separate people from their characters is a skill and most new role players don't have it. There are even really good roleplayers that can't do it simply because doing romantic stuff like that is a sensitive topic. 

Another reason is that the player is simply part of the fantasy. The idea that granting the character some sort of gratification is also granting that gratification to their player. Other times it's the opposite. Maybe they feel guilty about a certain type of fantasy they want to play so they seek out someone with a different gender than their character. 

[quote=@Ammokkx]
[url=https://i.imgur.com/zNrO5wx.png]I am the single cutest miqo'te this side of Eorzea and nobody's gonna stop me from being that.[/url]
[/quote]

[url=https://i.imgur.com/RVgETDN.png]Good thing I reside on "that" side of Eorzea less I have to challenge you for your title, as there is no miqo'te as cute as me![/url]

[s]If I ever get back into this game we should meet up and touch tails.[/s]