Xenophobic isn't quite the right word. Racist is closer, but even that misses the mark. Every story he writes is terrified of black voodoo savages, or toothless white hill people, or inbred decadent Boston brahmin families, or fishermen that are half-white-half-Chinese-half-fish.
Aristotle, by contrast, isn't that concerned with gender. He is happy to treat it as a topic, but he has nowhere near the same level of preoccupation.
I do think you're right that Lovecraft's ability to write effective horror was largely because he himself was fascinated with terror at the world. But I don't think his weird xenophobia is what he ended up actually communicating to most readers or what he's famous for. He's more known for misshapen tentacle monsters and cosmic-scale horror. For example, Lauren Beukes' novel Broken Monsters is often considered Lovecraftian horror, and it has fairly modern sensibilities.
Seriously though, why not call it "tribalist"?
More than the people of his time?
[1] https://web.archive.org/web/20060507063256/http://blog.urban...