Peter Kropotkin was surely on the left. He was one of the founders of what is now called 'sociobiology' or 'evolutionary psychology' with his book Mutual Aid, arguing that human nature had evolved in ways conducive to the communitarian anarchism that he espoused.
Noam ChomskyWe don't use the term 'working class' here because it's a taboo term. You're supposed to say 'middle class,' because it helps diminish the understanding that there's a class war going on.
Noam ChomskyThe Bolshevik revolution was a counter-revolution. Its first moves were to destroy and eliminate every socialist tendency that had developed in the pre-revolutionary period. Their goal was as they said; it wasn't a big secret. They regarded the Soviet Union as sort a backwater. They were orthodox Marxists, expecting a revolution in Germany. They moved toward what they themselves called "state capitalism," then they moved on to Stalinism. They called it democracy and called it socialism. The one claim was as ludicrous as the other.
Noam Chomsky