Had I lived in Iran at the time of the Iranian Revolution, the Islamic republicans running Iran today would have killed me at worst or put me under house arrest at best, like Iran's Red Princess Maryam Firuz in her last years, because I'm a socialist. But still and all, a majority of the masses supported, and still support, the Islamic republicans, because they are populist Muslims, not socialists.
In the history of social revolutions, it often happened that leftists helped to bring about social revolution (socialist or nationalist), and then, after the overthrow of the ancient regime, a faction of revolutionaries (usually centrists) liquidated left-wing and right-wing revolutionaries as well as defenders of the ancient regime.
That's what happened in Iran, too. The revolution did in its leftists, as well as rightists. But, over all, the Iranian Revolution has done more good than bad for a majority of Iranians, making Iran the best country -- the most democratic! -- in the Middle East today.
The fate of leftists in many countries (excepting Cuba) is often the fate of Rostam: serve the rulers who are unworthy of your support, because the nation ruled by the unworthy rulers still must be defended from its many enemies.