It's an amusing reference to the cheeky line from the historic Unix man page for `ed`; "the standard Unix editor".
RE: who decided.. well, the presence of `ed` was a requirement for an OS to be accredited as POSIX-compatible, so that's presumably why `ed` decided to describe itself as 'the standard'. But `ed` fell so far out of favor once screen-based editors (`vim`, `emacs`, etc) became commonly available that the "the standard" line which continued to hang around in ed's documentation became a bit of a Unix in-joke.
The modern GNU version of the `ed` tool describes it as "line-oriented text editor" instead of as "the standard Unix text editor". And only briefly mentions the old phrase in an apologetic explaining why that old phrase was used in the past.
So the short version of the answer: it's not. It's an in-joke which is attempting to draw to mind a comparison of this software against older, simpler Unix tools like `ed`. Which IMHO is totally valid, if you say pass is to lastpass as ed is to vscode. Simpler tool, possibly easier to use for keyboard-focused folks, focuses on doing just one thing and doing it well, etc.
