The very next sentence justifies why they didn't do it: it argues that they would have ended up with what was technically Zig but something that was much less ergonomic than what would be expected from Zig.
You can argue that that's a bad justification for not doing it, but that's a debate on the technical merits, not a claim that they didn't provide justification.
You can argue that that's a bad justification for not doing it, but that's a debate on the technical merits, not a claim that they didn't provide justification.