Mandras comes to idolize Hector. They steal a lamb one morning and Mandras thinks that with the lamb slung over his shoulders, Hector looks like Jesus. Hector carries a book written by Lenin called What Is To Be Done? and promises to teach Mandras to read. Mandras has already learned that he's a worker, not a fisherman, and it's the king's fault that the capitalists profit from his work. He now resents Dr. Iannis for being bourgeois.
It's worth noting that Lenin was fairly critical of religion and saw it as another structure that oppressed the proletariat. Mandras's assessment that Hector looks like Jesus (and the fact that in his mind, this is positive) suggests that Mandras still doesn't know what ELAS or communism are all about and is being manipulated.
When the shepherd asks for a gold sovereign in compensation for the lamb, Hector and Mandras laugh at him. The shepherd insists that EDES and the British always pay for their sheep. Hector threatens to kill the shepherd if he sells supplies to EDES. As Hector and Mandras walk away, Mandras calls the shepherd a fascist stooge.
The threats of violence and the language Mandras uses show that ELAS isn't at all concerned with helping the people it insists it's going to help. Just as dictators abuse their power, ELAS does the same thing to remain in power.