And in before “good job greek conservative government for making gay marriage possible”. The main opposition to gay marriage was the current government and even though it was their own bill, half of their mps voted against/abstained.
The government just wanted to disarm the opposition and knew that even though most of their voters opposed it, in the long run(once old people die), the majority of voters will support gay marriage.
And if they keep opposing it, it will have significant political repercussions, especially since the main opposition party just elected a gay leader. Also our prime minister is a CIA asset(thatcher conservative, not maga conservative), so that works too.
The bill passed only because most of the opposition voted for it(except for the communists and nazis).