Well to me the reason why is because I'm so socially disordered. I do have three female best friends (just friends), but that is because I could relate to them in some way. They were girlfriends and friends to my male best friends. To me it isn't so much about making friends, but rather starting a romantic relationship. Which I believe is what both aspie sexes have problems with. Starting a friendly relationship just means treating them the same way you do as your same sex's friends. The difference between this and romantic relationships, is that in romantic relationships you have to be the first one to climb the mountain before the other members of your sex do.
Aspies got being heroic, nice, smart, and intelligent down, but the main ones: flirting, joking, and independence. Are difficult for some strange reason I don't know and wish to fix.