Originally Posted by Unregistered

What makes more sense for "fairness" would be for the US to be able to run their own popularity contests and then share the reskinned versions for both contents across both regions. This would be a win-win for both regions and it means that US players are not excluded from the event.

That was originally the plan, they even said they'll release the JP winners in US eventually (which means the US winners would be released in JP).
But they changed their mind for reasons unknown, I don't think they'll ever reveal their true reasoning but all we can do is hope for some compensation.