The fact that they have flags for all of them and the linguistic weirdness of a lot of them* points to them having come out of the MOGAI movement, which coins as many terms for genders and sexualities (and other stuff) as people can think of and makes flags for all of them. They make terms for every conceivable experience, not just for experiences they or anyone else they know actually have. It's a very niche teen-on-tumblr-with-nothing-else-to-do thing.

*"Dreagenic" meaning "from dreams" especially jumps out at me that way - dropping the last letter of a morpheme like that reminds me of the MOGAI terms "womasexual" and "masexual" for "attracted to women" and "attracted to men."

Robin