Because we want to write correct code. We want to verify the absence of many types of errors where amateurish language war stuff like Rust vs C does not even scratch the surface.

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?