These are not two distinct oppressions. Religion is part of the superstructure (i.e. the state, the laws, the culture, etc.) which is held up by the class struggle and the socioeconomic dynamics of power. Religion, like the state, is simply the tool and not the cause of oppression.

In a capitalist society, the superstructural institutions are mobilized to protect capital. Those could and were effectively conquered by the oppressed class at times in recent history, including religion. An example would be liberation theology in Latin America, or the movements of Marxist Muslim scholars in Central and South Asia.