That's just plainly false. A std::sort() for examples beats a qsort() easily. C just doesn't have the tools to handle that kind of thing without a lot of manual code duplication.

The reason for not using C++ is simply that it's a huge monster of a language, that makes it difficult to find common ground for a programming style. In C that is much easier as you have much less features to worry about. It is more verbose and error prone, but also more predictable and easier to review, as the code you see is what you get in the binary. In C++ can have a mountain of stuff hidden behind operator overloading, exceptions and other stuff, which makes it very difficult to reason about.