"Holland" is not a country but a set of 2 regions within the Netherlands, similar to how Dakota ( Yes North AND South Dakota) is a part of the United States of America.
Specifically referring to two regions of a country rather than the entire country.

"Holland" comprises only two of the twelve provinces in the Netherlands: North Holland and South Holland.

Referring to the entire Netherlands as Holland is a common mistake, akin to calling the entire United States of America "Dakota," which overlooks the broader and more accurate national context.