A lot of people are probably just not familiar with the single-command envvar syntax, and of people that do know it some of them probably don't know the syntax

A lot of people are probably just not familiar with the single-command envvar syntax, and of people that do know it some of them probably don't know the syntax for unsetting. So it's just not immediately obvious to many why a simple extra space is a problem at all, and why it's this specific error. It can also just generally be hard to see past what you intended to write to what you actually did and how that will be parsed.