It's about dependability and bootstrapping. GCC 4.7 was the last version implemented in C, and it supports C++98/03 and a subset of C++11.
> There are some warts here and there that C++17 fixes [..] nothing major
But it's C++17 and thus requires many more bootstrap cycles until we have a compiler. I think a backend which only supports a subset of the features of a C++17 compiler should not depend on C++17, otherwise its usefulness is restricted by the availability of such a compiler.
> I do not get the fetishizing of C. String handling is just atrocious...
C is just a pretty primitive high-level language (with a very strange syntax) a compiler of which exists on almost any system. The next complexity step is C++98 (or the subset supported by cfront), which solves your issues and is even good enough to build something as complex as Qt and KDE.
> There are no plans to support 32 bit x86
Ok, thanks. The support for ARM32 already enables many use cases.