It's pretty obvious this is about immigration and origin, not income or healthcare.

Mesoamericans, which became Central Americans, and have since immigrated in large numbers to the US, tend to be shorter than Europeans.

Japan has some of the healthiest people on Earth, as measured by things like nutrition, healthcare, and lifespan. But they are still shorter on average than the much poorer Estonians.

It feels like the author is inappropriately shoehorning this data into a statement about healthcare.