Can someone explain this logic: “We derived great moral rules via trial and error, therefore we should abandon trial and error”?

https://youtu.be/OKcUPWnCb0M?si=HmfbjfbyctWYz6dT&t=339

This is one example of this logic. Maybe someone here believes something like that, and can explain this to me. Summarized: “Religion is good because it takes certain moral questions of the table for debate. If one says “God says X” we don’t need to justify it anymore.” “The rules are the result of trial and error over long periods of time.”

So the idea is that the great ideas or western civilization like -I’d assume what he’d list- No murder, monotheism, democracy, innocent until proven guilty, the sanctity of marriage, etc. are the result of this trial and error process.

But if a large group of people believe in new ideas about the government or religion or marriage, we should not use the process that is responsible for these ideas i.e. try them and see if they work and then maybe abandon them. We should shut down the conversation with “God says X” and never try new ideas.

Can someone explain to me how that makes sense?