The original post explicitly praised Zig, and seemed to be arguing more that Zig was a great tool for the initial version of Bun, but that Rust was better for their needs as Bun grew to a larger project with a larger contribution team.
That seems completely in line with what Zig claims its strengths are. Zig's response to "but memory bugs" has basically always been "Zig is not a language for a big tumultuous project that you're going to throw interns at."