>>The "Hispanic = non-White" is such an arbitrary distinction.
All racial distinctions are fundamentally arbitrary. From a genetic point of view, there is more variation among individuals within a race than average variation between races. The exception is certain central African people (often called "Bushmen" but that's a deprecated term). They descend from peoples who were less affected by the genetic bottleneck that most of the rest of us descend from (so they actually have more genetic diversity in their small population than the whole rest of humanity combined).
>>North America thing
In the particulars, yes. In general, though, most of these ideas are a legacy of colonialism in one way or another. I think most scholars agree with Hannah Arendt's classic Origins of Totalitarianism that racism and anti-semitism as we know them are mostly 19th-century inventions. Yes, people hated each other based on ethnic and national differences since humans have been humans, but the doctrine of race is quite modern. For example, in the 17th and early 18th centuries, Africa slaves who were brought to America were identified by nation and ethnicity. It was only after a major slave uprising where African slaves and poor whites rose up together against the plantation system that this shifted radically. By the late 18th century, manifests just listed African slaves as Black, because that was all that mattered.
It was also why the Southern states pushed hard for the Second Amendment, the right to bear arms. The well-regulated militia were intended to be ready to put down uprisings.
But the same general dynamic happened in every colonial region whether American, British, Dutch, German, French.
In the US, the "one drop" doctrine indicates also how arbitrary this is. By that doctrine, codified as law in several states prior to the 1960s, it stated that one drop of black blood made someone black. So someone who has 15 white great grandparents and 1 black great grandparent was legally black. That's how arbitrary these things are. The Nazis sent respresentatives to both the US and South Africa to study this when developing their Jewish policies.
