So why do you think Karin was made into an Uzumaki?

[JStar King]

Three years and you still don't know what retcon means. Anyway existence of other Uzumaki's with power chakra abilities other than Kushina and Naruto gives a bit of fleshing out to Uzumaki clan survivors of which were scattered. it doesn't have to have more or less relevance otherwise. She can be of any clan or family but her sensing and chakra abilities count and they fit in with Uzumaki's too, so why not? ( no it's not a real question).

The thought that there may be more suvivors out there after the Uzumaki's downfall really is intriguing.

Just imagine it.

 

[~Sasuke~]

Karin hasn't even showed up yet(If ever). He probably made her just to show that there's some surviving uzumakis around, i guess.

^^^^^