For me, choosing the language is not enough. It's the tooling that goes far beyond the language that is important for safety and quality of compiler and runtime. C has very mature tooling options. So does ADA.
https://www.absint.com/astree/index.htm
Abstract Interpretation in a Nutshell https://www.di.ens.fr/~cousot/AI/IntroAbsInt.html
Proceses that outside high integrity computing no one is willing to make themselves go through without legal requirements and liability.
Most of it because during 1980's it was cheaper to advocate for C plus certification than pay for Ada compilers and developers.
I would propose that we change your original statement "Ideally neither C nor C++ should be used when security matters." into:
"Ideally people who don't care about secrurity should not write code when security matters."
Can we agree that this is better than talking about programming languages?
And that is precisely what they said:
> Ideally people who don't care about secrurity [sic] should not write code when security matters.
The absence of legal consequences further supports the fact that it does not matter.
https://www.google.com/search?q=any+case+law+to+defeat+this+...
Naturally the move fast and break things culture sees it otherwise.