1) Rorschach is at least infatuated with Dan. At least. And this isn't even necessarily a fanfiction thing alone. The lingering handshake says a lot about their relationship.
2) Rorschach is everyone's favorite. Fans and characters alike. He is the Wolverine of the Watchmen universe.
3) Handjobs are the most popular form of sex in the Watchmen universe. Especially in Rorschach/Nite Owl stuff.
4) Laurie/Adrian is way more appealing than it should be.
5) Adrian is a huge narcissist and most of requests involving him on the kink meme are masturbation or clonecest.
6) It makes most writers more comfortable to think of Kovacs as a separate entity from Rorschach. It certainly makes it easier to imagine him being at all interested in sex in the first place.
7) Dan's impotence is only a problem in the normal canon. In fanfiction he's a sex fiend. Still, I'm considering writing a fic about how Dan can't get it up and Rorschach can't help but get it up.
8) As many times as people include the Comedian in fics, I can't bring myself to be the slightest bit interested. It's strange, considering what Rorschach and Adrian have done that I can still like them and be interested in them, but the Comedian bothers me. Don't know exactly what the line is.