No democratic Socialist would oppose the state legalizing gay marriage. Nor would any Marxist educated socialist join in any " politically correct " faith bashing. On the so called Left there has been much lying vilification of the Catholic Church. No honest liberal would accuse the vast majority of Catholics of having hatred in their hearts for ANY group on the planet.
Pope Francis was right to suggest that his Church had become too obsessive in defending ancient -and perhaps ossified-views on homosexuality and abortion.
The " greening of Catholicism " has seen a broadening of its PRO-LIFE perspective. What can be more anti-Life in the modern world than over-population and the sick values of Ayn Rand capitalism ?
And traditional Marxism never sentimentalized " bourgeois " state marriage- a pillar of inequality and private property.