Incidentally, Orwell fought in the Spanish Civil war as well under the POUM, and went on to write a book about it. What he saw in Catalonia solidified him as a Democratic Socialist for the rest of his life, and soured him on totalitarian communism after seeing how the communists betrayed the Anarchists and the POUM, which inspired him to write Animal Farm.
I recently read this and was surprised at how good it was. I loved Orwells Animal Farm, but didn't like 1984 that much, so I wasn't expecting to enjoy it; I read it more to get some insights of the war. But the book is not just informative, it is also really funny at times, and the story is just wild.
Betrayal is a bit of a hefty charge to be leveled against anyone by the guy who turned government informant and denounced writers he thought were too communist to the British government.
Betrayal is about the only word to accurately describe the historically documented events when Soviet-backed communist troops began firing on non-Soviet-backed communist and anarchist troops in the middle of the civil war.
Or the summary executions of individuals that criticized the growing Stalinist influence. Hemingway rather famously had falling outs with several of his friends for ignoring other friends being executed in the street.