All anarchies are not socialist. Many are not. The people telling you this want to make a convenient erasure of what falls outside of their program. They want to be the Answer, the One True Anarchism. Many anarchies are neither capitalist not socialist (in the traditional sense of the word socialist). People like Landauer have used the word socialist in other interesting ways, but for the most part socialism means a commitment to, among other things, economy, politics, bureaucracy, etc. Many anarchists are against these things and also capitalism. What socialism and capitalism have in common are an obsession with political economy, and a tendency to frame all of life in terms of economy and production, but there are many who do not care for playing number games and a life of toil.