[viccis]

>> whereas humans almost always tend to use a slang version - a single dash with spaces around it.

>That's not an em-dash (blahblahblah...

What, exactly, did you thing "slang" in the phrase "slang version" meant?

[dragonwriter]

It was an abuse of “slang” to mean “typographic approximation”; now what, exactly, did you think “and its not even an approximation of one, using a hyphen-minus set open—possibly doubled—is an approximation of the typographic convention of using an en-dash set open” meant?