Ez, ez gara. Maybe, 100 years ago, but the Basque Nationalism shifted away from the alleged far right, traditionalistic and outdated politics (Sabino Arana) to the cultural, civic, values related nationalism about 70 years ago. Call us chauvinistic, but not racist, because even Black people speak better Euskara here than most non-Basque Spaniards.
And, OFC, they are considered as Basque as anyone else.
I'm referring to the modern Basque independence movement, not the historical Basque ethnicity or ethno-nationalization movement of the early 1900s that has been subsumed by the geopolitical independence campaign of the 21st century.
Not even in the 21th Century. The late 20's had Socialistic shifts on what could be defined as Basque. Arana's mindset went downhill fast as the Romanticism theories were replaced with shared culture traits to define a country.
Custom traditions and the language had far more weight than how did you look. Specially here, where, in Iberia itself, had multiple-way Religion conversos since several millenia.
Maybe the Americans are used to Race = Ethnics = culture. Here it doesn't work like that. It's the surrounding culture what defines you in the end.
If your parents came from Africa you are African-descendant, but if were born and lived in the Basque Country you are Basque and not African, period.
And, OFC, they are considered as Basque as anyone else.