Yeah, this never works out.
Multiples of the same basic community is a good thing. It was good on reddit, and it's part of the entire benefit of federation. The only difference is that, here, the displayed names can be exactly the same because the C/ always comes with an @ as well.
While it would be nice if location based communities had an agreed on standard, good luck getting consensus between even the five biggest instances and all of those C/s. It would be a herculean task. And, it still wouldn't stop anyone else from just ignoring the consensus.