Described, yes, obviously. Classified, in the literal, biological sense? No. And your logic is the same of those who conceived these labels, the same reason they exist -- large groups share a significant number of similarities? Again, no two people share the same sexuality. So similarities mean shit. Grouping "similarities" where something so subjective is concerned is just a quick, sloppy, politically incorrect way to categorize and further humankind's attempt to define and make everything "known." If anything, those groups are only defined by the acceptance of labels. So you're okay with being labeled a "gay," despite the fact that you do have/have had a slight tendency for females. What about those who don't have such a narrowed preference, i.e. the majority? You cannot put that in a box, and if you do, you'd be out of line.
And clouds aren't subjective doll. Clouds are measured by shape and density and such. Can you measure my level of attraction to guys and girls? Can you also give it an appropriate name that accurately defines me but also works for everyone else? No. You can't.