I guess it is a consequence of the Reddit migration where the habit is just keeping the old community name. But having C/Politics being US only on Lemmy.world, an instance that aims to be international (hence the name), seems weird to me.
Would have been cool to give up this assumption that everything is related to US by default when moving away from Reddit. I mean, even the canadian political news of Lemmy.ca is CanadaPolitics.
If it was on an instance named america.yeehaw that was clearly US centric it could make sense in that context.