It said it was able to correlate where you live (I don't think it said anything about the tone, unless it said more than you included in the article). At best, it's really just using that for justification though. The model can't feasibly search the web for your writing style. That correlation had to be trained in.

My point is that, if you created a new account and actively used it for a while, I don't think the current version of Grok (never trained on your new account) would ever be able to make that association. It's certainly interesting that it could do it, I just want to drill into the how.