[Jess Kitting]

"Over the years, Cuomo has shown a healthy dose of contempt for the working-class Americans

What is healthy about contempt for your fellow Americans?

He's one sick guy. His brother is another one.

[oldvirginian]

“What is healthy about contempt for your fellow Americans?”

A healthy dose means a large amount.
Saying Cuomo has a healthy dose of contempt for working Americans means he has a large amount of contempt for working Americans.
It has nothing to do with actual health.