Alleged to have begun with
Richard Hell, as an anti-
glam statement.
Clothing that would be more befitting a
derelict, torn, maybe held together with a
safety pin or two.
An example from Roman Kozak, a chronicler of those CBGB's days: Hell's torn and defaced Bugs Bunny T-shirt; Bugs has a leather jacket on, Hell's addition was the phrase "Bugs Bunny has too much money". A starving artist can't afford a jacket like Bugs', after all. Johnny Rotten did a similar thing, scrawling "I Hate" in front of the band name on his Pink Floyd shirt.
Later, designers would try to sell you pre-torn T-shirts, or design non-torn ones based on the DIY-modified shirts. Plus ça change...