Anarchism exists within socialism too-- the anti Francoist anarchists in Spain who were crushed by Soviets for doing the wrong kind of socialism, for example. Kropotkin's approach and anarcho syndacalism is anti-statist, and also anti-capitalist.

Anarchism is a complex area that can be capitalist, socialist, individualist, collectivist, primitivist, techno..logist? Basically, like communism, anarchism doesn't have just one flavor.