I think Sirlin's definition of a "scrub" is interesting, and certainly useful (in that it describes a type of player that exists), but I wouldn't read too much culturally into that definition.

It might have something resembling that meaning in the Street Fighter community (though, as far as I know, it's still way more general than described in this article), but, for video games in general, it is mostly used to mean "just a bad player."