I mentioned performance and game development specifically. I'm sure you're aware that it's common to write C++ that's very close to C while taking advantage of few features of C++. I don't think it's fair to call that the "diametric opposite of C".
Your opinion of Hare's view of simplicity is your opinion. Any software effort has some amount of essential complexity, in my experience many languages and tools quite a bit of incidental complexity that could be avoided.
You can write bad code in any language. (We used to say "you can write FORTRAN code in any language", back when.) C code compiled with a C++ compiler is C, and bad. With the C compiler, you had no choice. You do not get that excuse when you have a C++ compiler.
Avoiding unnecessary complexity is everybody's responsibility. Dumping every last bit of unavoidable complexity onto the programmer where it has been long demonstrated that tooling can take care of much of it is simply irresponsible, and inexcusable.
Your opinion of Hare's view of simplicity is your opinion. Any software effort has some amount of essential complexity, in my experience many languages and tools quite a bit of incidental complexity that could be avoided.