Maybe a bit more in New England, but that's just it: New England isn't all (or even very much of) of North America. There's a couple answers in that thread that seem logical, and several others that make my blood boil over ("hurr-hurr, all English racist dicks, all Iberians racially-accepting horndogs"



), but I'll grant the person mentioning King Philip's War as a contributing factor seems to be well-read and clear on his theory. The issue is, there's way more to Anglo-Indigenous dynamics than one conflict.
As brought up in the same thread, the Spanish had it relatively easy (not to mention bags of dumb luck) when they came upon the Aztecs and Incas; they were quite advanced societies even by European standards and well-populated even post-plagues, so there was pressure to incorporate larger numbers of said natives as conquered subjects given the lack of numbers of Spanish settlers (and that whole argument about Iberians being racially mixed already is both factually
wrong and a non-sequitur, it wouldn't matter too much who did the conquering with the same race-gender imbalance). Portugal had an even smaller population than Spain, yet held a relatively huge stretch of South America to control; factor these two elements in, and you'd see why Brazil saw similar racial dynamics despite the lack of a "central society" as previously mentioned.
In England's case, the natives were largely tribal/sub-national in governance and political character, which set the stage for later massacres and conflicts to be conflated as "civilized vs savage" persons fighting over resources/land. On top of that, the English adopted a policy of sending whole families to New England due to its source as a religious colony (it took longer to show up in Virginia, which was mostly a resource-extraction colony for most of its history anyway). We also see this in other parts of North America (regardless whether under American or British charge). France had a policy of essentially "colonies without colonists" beyond a city or two, plus fur traders, so there'd be no pressure for conflict as much. Even if King Philip's War didn't happen, that wouldn't effect other colonies' dynamics (e.g. Bacon's Rebellion being very much focused against tribal groups in the Upper South). Not that you COULDN'T have such colonies develop more mixed-race populations, there's nothing inherently racist about England any more than the Spaniards in truth, but you'd need to see the colonies be established with less of a "whole families, whole communities" dynamic going back to the late 16th Century (early 17th Century at the latest).