I don't either!! Like if someone is "kin" with something else to relieve stress or just for fun or something, that's fine, but- and I might get hate for this- if a human being is going around and seriously believing that they are not a human being but an animal or fictional creature instead, there is something wrong with their head. There is no way there is not something wrong if you look at yourself and don't see a human being but like... a fox instead.
I should probably throw out there that factkin (people that id with other REAL people, dead or alive) are EXTREMELY problematic (it's borderline impersonation in a way) and most of the time aren't accepted into the otherkin/fictionkin community. The easiest way I can explain otherkin/fictionkin is having a very strong connection to an animal or character, so much so as that they identify with them. Most of the time otherkinism/fictionkinism is used to help deal with identity issues, so that people that struggle with those issues can have a sense of self. Other times it can be a past life, where someone has memories of being a character or animal. There's also times when something traumatizing happens to someone, and they find a character/animal they relate to or identify with, and they kin with them to cope with their trauma.
I'm the same way honestly. I don't see how someone can identify as Sans or something. Like I get gender identity, Im fluid myself, but identifying as a video game character? Not hating, just questioning