Would you similarly oppose the requirement that all civil aviation globally be done in English on the grounds of “cultural imperialism”?
There is a very visible pattern in most Open Source projects where a small group of core maintainers will do most of the work even if there is a much wider body of causal contributors (see Nadia Eghbal's _Working In Public_). So, what are the economies of scale? Are you perhaps referring to problems experienced in the by-gone age of the early internet?
Economists largely agree that healthy competition is beneficial for improving quality, spurring innovation and reducing costs. I don't see the problem with multiple language/culture specific software projects that all solve the same problem. This could even look like different programmers working on different projects for different audiences.
The only downside I can see for the everyday programmers is the FOMO generated from inaccessible software in a foreign language. Isn't that ironic?
Do you think that every pilot on earth always speaks only English? No.
People should have the choice not to speak English and write their alphabets if they wish.
Enforcing ASCII on code is like enforcing ASCII on URIs, e-mail addresses. Unnecessarily restrictive to the rest of the world outside of the anglosphere. Of which there's a lot.