This is a misrepresentation of the facts. Zig can use libcurl just as much as C can. Unlike other languages, zig does not need bindings to use C libraries. It's one of the main features.
The issue you linked is saying tht zig standard library will not introduce a dependency on libcurl.
https://github.com/ziglang/zig/issues/2007
granted neither does C, but C has cURL, and Zig doesnt (and wont) have cURL binding:
https://github.com/ziglang/zig/issues/2056