The history of slash has been pretty well discussed in a few books. That it's lasted for decades and grown in a lot of different directions should be enough to demonstrate that it's not just a matter of a few stories by people who don't get that Kirk likes girls; there's something more complicated going on. The amount of academic writing it's generated should prove that. It started as gay porn by and for straight women; from what I've read, in the early days, at least, gay men never bought into it, and their input was not particularly welcomed by the slash community. Also, IIRC, slash always had a somewhat suspect reputation, despite its popularity, and many writers and publishers operated under pseudonyms.
For an ethnographical look at slash in the print fanzine days, see Camille Bacon-Smith's Enterprising Women (which has a few pages on Killing Time) and Henry Jenkins's Textual Poachers. They're both academic works but also quite readable. (They're not just about slash, but deal with it as a major element of fan fiction.) For a somewhat more theroretical approach, try Constance Penley's NASA/Trek.
For an ethnographical look at slash in the print fanzine days, see Camille Bacon-Smith's Enterprising Women (which has a few pages on Killing Time) and Henry Jenkins's Textual Poachers. They're both academic works but also quite readable. (They're not just about slash, but deal with it as a major element of fan fiction.) For a somewhat more theroretical approach, try Constance Penley's NASA/Trek.