Their citizenship status is the issue.
They were not US citizens at the time of his birth. They were citizens of Cuba making Rubio a dual citizen at birth whose parents were not under the jurisdiction of the US at the time.
Marco is a citizen of the USA but not an NBC.
My son was born in the UK of parents who were both USA citizens. He is a dual national with two passports. He can hold any office in the United States with the exception of President or Vice President.
The Constitution means what it says.