Spanish were more shady than the British/Irish/Scottish.
Spain mostly sent over men, and they were wayyyyy outnumbered. So instead of separating everyone on race, they created a "pan Hispanic" identity. Everyone is some degree of white/Spanish from criollo to mulatto, zambo etc. Much more complex race structure.
In North America, the northern Europeans came in larger numbers. They mixed with or raped Blacks (brehs & pawgs mixed in the 1600s then white men raped sistas from 1700s on). They didn't need a complex hierarchy. It's Black and it's white. This meant Blacks and mixed Blacks mostly were under the same umbrella. We kept a separate identity and culture that's NOT based on proximity to whiteness.
Throw in Blanqueamiento....actively recruiting Italians, Germans etc., to whiten up Latin America and....this is what you get.
Dominicans are much more mixed than we are....but Black Americans that look like Dominicans would view themselves as "Black." Not Irish or Scottish.