but even slightly degraded complex once-alive compounds would be better than ground rock and water to have life start again?
Yeah, the conversation was about organic molecules, not living organisms. And when I said oxygen would make them degrade, I meant it would destroy them. They need to reach certain lengths to start replication or one of the other hallmarks of life, and oxygen is so greedy for electrons that it doesn't let them do that.
It's one of the great poetic developments of biochemistry that so much of life now depends on oxygen, which is so toxic.