In his response he actually juxtaposed the word against “globalist”. i.e. there are nationalists and there are globalists.
“White nationalist” is a label for a group that wants a “white nation”. Nationalist is a lable for a person who values their nation over all other nations.
They are not stupid. They are being intentionally obtuse to persuade the stupid.
The word White no more associated with nationalist than it is paint
Not all nationalist are white nationalist just like not all paint is white paint