If a candidate were foreign born, they’d be ineligible. If they were under 35, they’d be stricken as well.
We have rules regarding eligibility. If you break those rules, you’re no longer eligible.
If a state court removed a candidate because they discovered that they were actually a Canadian citizen, removing them from the ballot isn’t “deciding” who we’re allowed to vote for. It’s applying the rules.
Imagine if slavery were left up to the states…