C++ was not a force in 1987, so it is decidedly peculiar to mention it at all. And, even in 1987, malloc and alloca were both available everywhere. So, no, this is propaganda; not important by itself, except insofar as it unmasks the authors' biases.
Annnnd, C99 VLAs as such were not in C++11 at all, and were removed ("made optional") in C11, recognized as a mistake. That does not, of course, mean that C or C++ functions' array arguments were ever restricted to a fixed size.
Annnnd, C99 VLAs as such were not in C++11 at all, and were removed ("made optional") in C11, recognized as a mistake. That does not, of course, mean that C or C++ functions' array arguments were ever restricted to a fixed size.