Guess what? People don’t choose their kintypes. Wild, right?! If you are picking your kintypes then I’m sorry, that might just be a favorite character rather than a kintype. It’s similar to sexuality or gender: you don’t choose it, you just are.
You telling me to stop being kin with something is like telling me to stop being pansexual. To stop being genderfluid. “You’re not disabled so you can’t be kin with Cinderpelt!” “You were born a female so that’s your only gender!” “Pansexuality isn’t real because you can only like one gender!”
If you’re kin with something, you cannot stop being kin with them. If you can just REMOVE a kintype, that is not you being otherkin, that’s you just really liking something and relating to it in a not-kin way.