Watching all this, Orwell arrived at some conclusions that clashed with leftist conventions of the era. At a time when leftist solidarity was considered mandatory, the right thing to do, Orwell began to harbor suspicions. Observing the fighting in Barcelona between different antifascist factions, he noted, "You had all the while a hateful feeling that someone hitherto your friend might be denouncing you to the secret police."
In effect, the events in Barcelona forced him to examine the left as he once earlier had scrutinized imperialism and capitalism. He concluded, "The Communist Party, with Soviet Russia, had thrown its weight against the revolution." It was determined to systematically wipe out the anticommunist parts of the left—first POUM, then the anarchists, and then socialists.
But to say this in public was a form of modern heresy. Orwell realized, with shock, that the left-wing newspapers did not report the situation accurately, and did not want to. Rather, they willingly accepted lies. "One of the dreariest effects of this war has been to teach me that the Left-wing press is every bit as spurious and dishonest as that of the Right," he wrote. This set him on his life's work, to push continually to establish the facts, no matter how difficult or unpopular that might be.
-Thomas E. Ricks, Churchill & Orwell: The Fight for Freedom