Because the C++ compiler accepts an absolutely insane variety of code styles. I say this as someone who mainly writes C++. If I write my own project, or a project where I only have to work with a small number of people all of whom I know have extensive C++ experience, or a project that is so large that I can afford to consistently rewrite parts, educate contributors and maintain style guides, I choose C++. But anything that doesn't hit these bells, I'd rather use C (or something else). People mixing completely different styles in C++ is a nightmare.
> People mixing completely different styles in C++ is a nightmare.
This is really not my experience. Any decent-sized program will have parts more in a functional style, others in a more OOP one, others in regular-typed Stepanov bliss, others in template or constexpr metaprograms.... and this causes zero issues in practice once people get past their assumptions about what clean code should look like.
