Goodness is about character - integrity, honesty, kindness, generosity, moral courage, and the like. More than anything else, it is about how we treat other people.
To understand the Left, one must understand that in its view the greatest evil is material inequality. The Left is more troubled by economic inequality than by evil as humanity has generally understood the term.
Society may no longer define marriage in the only way marriage has ever been defined in the annals of recorded history. Many societies allowed polygamy, many allowed child marriages, some allowed marriage within families; but none, in thousands of years, defined marriage as the union of people of the same sex.
In various European countries, it is increasingly common for young men to live with their parents into their 30s and even longer. Why not? In the welfare state, there is no shame in doing so.