Capitalist Casualties was one of Southern California's original powerviolence groups. Powerviolence, essentially a combination of hyper speed hardcore and grindcore. Its nascent form was pioneered in the late 1980s by Californian band Infest. The microgenre solidified into its most commonly recognised form in the early 1990s, and is defined by bands like Man Is the Bastard, Crossed Out, Neanderthal, No Comment and, of course, Capitalist Casualties. Much of the scene centred around the 921 Gilman Street venue and a label called Slap-A-Ham Records. Do some Googling if you're not familiar, you might be into it.
Here's Shawn singing with Capitalist Casualties in 1987: