You must have confused Perl with another programming language. Perl has always been a memory-managed language with a reference-counted garbage collector.

The link you posted doesn't even mention Perl at all. It does say that:

Using a memory safe language can help prevent programmers from introducing certain types of memory-related issues. Memory is managed automatically as part of the computer language; it does not rely on the programmer adding code to implement memory protections.

Perl clearly fits the definition of a memory-safe language with automatic memory management. The funny thing is that this document lists Delphi/Object Pascal as memory-safe languages, even though there are clearly not.