Archer said:

If people's stated kintype is influenced by cultural representations of that kintype, what matters is not how often the representation appears. What matters is how affecting that representation is and how well it speaks to the individual on a personal level.

 Well, that's one of the reasons that I picked centaurs specifically.  I know for a fact that there are a lot of people out there inspired by centaurs and who heavily empathize with them.  Both the furry and the transformation communities have significant numbers of people who portray themselves as centaurs or equitaurs (centaurs with equine heads atop the human torso).  There are even all-centaur RPG forums.  Clearly, centaurs speak to individuals on a personal level.  Yet I still don't see centaur otherkin around, even on the Genus Equus therian/otherkin forum which has a section specifically for them.

Most likely something else (most of them have been around longer than the Harry Potter stuff).  But if we assume that certain kintypes are more likely because they are more popular, then shouldn't the popularity of centaurs translate into them being a somewhat popular kintype, regardless of which specific media they were inspired by?