The author claims that the rules described, "extending" the standard C++, are enforcing memory corruption, and it is this author described subset that is still unsafe, not C++ in general. Think about english vs. americanized english, largely the same, but two distinct entities.
In C++, you are free to shoot yourself in the foot. In Rust, you have a Government inspector ensure that you always point the gun not just in a "safe" direction, but only toward a crosshair target at a designated gun range.
Any questions?