But that doesn't mean domain names should, or identifiers in programming languages. Those are critical, fairly low-level technologies, and allowing all of Unicode raises significant security concerns. I strongly believe those concerns outweigh the usefulness of non-Latin characters in those contexts.
The accusation of anglocentrism is unwarranted here. Every mainstream programming language ever created has all of its keywords based on the English language, including languages like Ruby and Python whose creators aren't native English speakers. This isn't anglocentric, it's a best-effort attempt to make the language as universal as possible in the world we live in. Internationalization at this level of technology simply leads to fragmentation. Domain names and programming languages are very different from user-focused free-form web content.