Two things.
One is this: nature does not work like you guys think it does. Its power is in producing apparently senseless types like us mama's basement dwellers because they may at some point in time be important for survival of the species. As unlikely as it may sound to you. If that were not so we would not have gays among us because they would be die off. We still have them around.
Second thing is this: I am a basement type (have my own by now), I dislike social environs because they confuse me and I see no point in casual conversations in such setups, most of the normalos do not enjoy conversations with me all that much either so all is well. Yet I managed to get involved 'romantically' anyway and to pass on my genes. Well to be true I did not run the test so I just think I did - still I had some warm body to play with and reproduce. I returned to my basement years ago and go out only for exercise, work, food acquisition and some such, I also give up my basement life style when kids are around. So both things happen - random deviation in how genetic makeup works produce all different sorts of beasts and even the least attractive beast (from the perspective of majority) can find another beast ready to cooperate in reproduction like activities that, even if only accidentally, may actually produce offspring.