So what happened in Catalonia that makes anarchists hate Marxists (on top of the free territory and Kronstadt)...

So what happened in Catalonia that makes anarchists hate Marxists (on top of the free territory and Kronstadt)? I thought the Spanish syndicalists were aligned with the POUM, which was a Marxist party. My knowledge on the events is not large at all and I wanna get into studying the events there. Sso, as a Leninist myself, a tl;dr of at least the anarchist-Marxist conflict there would be enlightening.

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The anarchists joined the Spanish Republican government in violation of their "muh liberty" anti-state rhetoric and then get wrecked by the Communists backed by the USSR in the May Days. Ever since then anarchists have had a burning hatred of things that work like proletarian states, organization, and socialism.

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Why?

Why did the communists decide to fight the republicans also?

Thanks for the post.

The POUM were trots .
Had the stalinists not betrayed the CNT, the trots eventually would just like Trotsky himself did to the Black Army.

becuz anarchy

I like the banter but I'd like an actual explanation. I'm sure they didn't do it without reasons.

From Wiki:
In spite of the fact that anarchist philosophy was against centralized government of any form and that the CNT-FAI had always shunned parliamentary politics while attacking the Socialists for collaborating with the state, by September 1936 they had decided to join the Generalitat of Catalonia. The CNT feared that arms would be withheld and that they would be isolated if the Generalitat under Lluís Companys formed a government with the Unified Socialist Party of Catalonia (PSUC). CNT members filled the Ministries of Health, Supplies and Economy and the Central Anti-Fascist Militia Committee was dissolved.

Soon after, the CNT also joined the national government. On October 18 a CNT plenary session of the regional federations granted the national committee secretary Horacio Martínez Prieto full powers to conduct negotiations with prime minister Francisco Largo Caballero. CNT representatives Juan García Oliver, Joan Peiró, Federica Montseny and Juan López filled seats in Caballero's cabinet. They took control of the national ministry of justice, industry, health and commerce, respectively. The CNT saw this "maximum concession compatible with its antiauthoritarian spirit" as crucial to winning the war. There was widespread friction and debate between the "collaborationist" and "abstentionist" anarchists in the CNT. Many anarchists outside of Spain (such as Alexander Schapiro) criticized CNT-FAI for entering into the government. There was also concern among anarchists with the growing power of Marxist communists within the government. Anarchist Minister of Health Federica Montseny later explained: "At that time we only saw the reality of the situation created for us: the communists in the government and ourselves outside, the manifold possibilities, and all our achievements endangered."

Some anarchists outside of Spain viewed their concessions as necessary considering the possibility of the Nationalists winning the war. Emma Goldman said, "With Franco at the gate of Madrid, I could hardly blame the CNT-FAI for choosing a lesser evil: participation in government rather than dictatorship, the most deadly evil.

Because they needed allies with access to foreign aid (foerign powers are usually not stupid enough to give weapons and supplies to rebels without a government that can somehow pay them back down the road) and chose the French-backed SocDems over the Soviet-backed stalinists. They chose poorly.