From Merriem Webster.
Simple Definition of ethnic
: of or relating to races or large groups of people who have the same customs, religion, origin, etc.
: associated with or belonging to a particular race or group of people who have a culture that is different from the main culture of a country
You proved my point. Trump metioned his Mexican heritage. Heritage is where your ancestors are from. They are from Mexico in this case. It has nothing to do with ethnicity.
Most Haitian (origin) people are black (race) but they identify as Creole (ethnicity).