-Assuming the EU is democratic and China is communist, why haven't they condemned Britannia for its human rights violations in Japan? How exactly do international relations work in the world of Code Pizza Hut? There's no UN, nor League of Nations, so where do people go to voice these problems?
The EU is at war with Britannia, although the tv series barely touches on that most of the time. China is just handling their own issues.
-What about the Native Americans, Africans, and Pacific Islanders? I'm guessing racism is still a thing, so are all these peoples still subjugated in the same way Japan was?
I can't remember who controls Africa in Code Geass, but Britannia doesn't have "Areas" inside North America itself, so, even if there's racism, it's likely closer to real world's than Japan's "Area 11" situation.
Why did it take Britannia so long to conquer Japan, then?
They only invaded Japan once Sakuradite became known and relevant.
-How is China still a country if Britain is all power hungry like this? What about India?
In Code Geass' world, they were weaker than in the real world and the royal family got kicked out of Europe to America. It's only after getting there that they become the super powerful Britannia.
-Most importantly, how come Blind Girl can't tell Zero is Lelouch? He barely even modifies his voice. Unless its a huge difference in Japanese and they don't address it in English.
I haven't watched the dub, but I agree that it's kind of weird. IIRC, Zero's voice had a small echo, and Lelouch usually didn't speak as fiercely as he did as Zero, but the voice really wasn't that well disguised.