I lived in the Netherlands for 7 years. North and South Holland are just two of the provinces of the country called the Netherlands.

They call themselves Netherlanders - not Dutch. This latter term was coined by the English-speaking world back in the 19th century and simply arose out of confusion. The "Netherlanders" never had anything to do with the term.

And just a little aside: The country of Netherland should NOT be confused with the "Low Lands", which is a 17th century term referring to the combined area of (most of) Netherlands and Flanders, which were below sea level.