That's because Spanish colonials were pretty open about interracial breeding. There were hardly any women sent from Spain, so they resorted to the native populations for companionship/sex/rape/etc. Sure, "Americans" have mixed with natives and African slaves, but it was taboo.

In the English colonies, it wasn't uncommon for entire families and religious communities to come over all at once. The natives in the Chesapeake region weren't appealing to these colonists as a result. And once blacks started being shipped over for labor in the colonies it was the same story there as well. I'd argue this has a lot to due with the fact that the people in the English colonies came to the Americas with, usually, the goal of creating and preserving their own insular communities and religious cultures.

The Spanish and Portuguese, on the other hand, didn't view the colonies as a place to "settle down" necessarily, yet the Spanish did support intermingling to a degree in order A) convert the natives to Catholicism and B) better manipulate a perfectly functional workforce of natives. I wouldn't say the Spanish or Portuguese were less "racist" (wasn't even a term back then because of how obvious and prevalent it was), but they had a different view of how to control the natives in their colonies than the English did, and they were pretty united under Catholic doctrine to justify it more neatly. The Spanish also had a lot more people to deal with than the English colonials, so while the English colonists could try to ignore the natives until they could expand, The Spanish needed to assert needed to be far more proactive about their claim over way more land that had way more natives on it.