This was produced, as a joke, with a nod to the Kinsey scale. Tom Limoncelli places bisexuality at the top in a deliberate attempt to promote a bisexual agenda, disliking Kinsey's suggestion that a bisexual person is equally heterosexual and homosexual. In fact, it allows for the vast majority of bisexuals to be somewhere in the middle. ("They like that kind of thing!") The Limoncelli Scale of Sexuality then implies that non-bisexuals are "far from normal" being right at the bottom of the scale.
0 = Bisexual: Equal attraction to both sexes ("50/50 bisexual")
1 = Slightly more attracted to one sex than the other
2 = Blah
3 = Blah
4 = Blah
5 = Mostly attracted to one sex, with a little exception.
6 = Monosexual: Incapable of being attracted to more than one sex (100% hetero or homosexual)