"Memory safety" is a term of art meaning susceptibility to memory corruption attacks. They had to come up with some name for it; that's the name they came up with. This is a perennial tangent in conversations among technologists: give something a legible name, and people will try to axiomatically (re)define it.

Rust is memory safe. Go is memory safe. Python is memory safe. Typescript is memory safe. C++ is not memory safe. C is not memory safe.