Ah yeah, Greece totally fought against communism /s
During WW2, the defacto resistance group was the communists, so most people joined them(even if they werent really communist). There was a right wing resistance group but it was much smaller and less relevant. After WW2, the communist resistance group had literally millions of members and obviously wanted to be part of the government.
That was not desirable by the british(and the americans) for obvious reasons. They demanded the disarmament of the communist group in exchange for some minor role in the new government. Eventually the deal broke down and the communist group protested. Then things turned to violence, leading to the greek civil war.
The greek civil war was the bloodiest conflict in Europe after WW2, till the war in Ukraine, with over 150k dead, most of them civilians. And because the right wing was outnumbered, they freed and armed the nazi collaborators. If you are wondering why a literal neonazi party was polling 15% at some point in Greece, was because the nazi collaborators were not only never punished but actually rewarded.
https://en.wikipedia.org/wiki/Dekemvriana
https://en.wikipedia.org/wiki/Greek_Civil_War
https://en.wikipedia.org/wiki/Security_Battalions
From the Security Battalions wikipedia article
After the liberation, the groups were only temporarily disbanded, and were recruited into the Gendarmerie to fight alongside the British and government forces against the EAM/ELAS in the battle of Dekemvriana in Athens. The Security Battalions always surrendered to the British, who usually let them keep the weapons the Germans had supplied them with.[24] General Ronald Scobie, who commanded the British forces in Greece, in contrast to his attitude towards EAM, whom he dismissed as mere "bandits", treated the Security Battalions as a legitimate military force.[25] The British Prime Minister Winston Churchill had a very favorable view of the Security Battalions, saying, "It seems to me that the collaborators in Greece in many cases did the best they could to shelter the Greek population from German oppression"
The greek civil war still remains a taboo subject in Greece and it isnt taught in schools(because how do you teach that "the bad guys won" to kids). Remember, throughout history, the good guys always win eventually. Winners write the history and they are always the good guys.
PS Stalin didnt help the greek communists because he had agreed with Churchil that Greece would be part of the "West".