Your argument here boils down to 'we shouldn't care if it's created in a lab, because even if it were, the benefits of studying viruses outweigh the risk'. It's funny that you accuse others of being 'armchair experts', when you yourself are being an armchair expert on the topic of the risk/benefit analysis of gain-of-function research. Moreover, your idea is even more dangerous because it necessitates that there will never be any expertise in this area. If no one investigates whether this was a lab leak, we'll never be able to put together proper research and data to answer the question of whether the benefits outweigh the risks of gain-of-function research.
The main purpose behind determining if it's a lab leak is not to 'make jumps'. It's so that we know. It's important we know because it's how science and policy get done. Putting our fingers in our ears and covering our eyes and pretending it doesn't matter is irresponsible.
> We've still not proven that COVID was a lab-leak, so we're attempting to say that something that otherwise has a very safe record is dangerous based on what might have happened.
How is anyone supposed to prove or even provide evidence of such a thing if China doesn't cooperate? And that's really the reason this has exploded. China is not cooperating. No one knows, and that's suspicious.
Even if, as you say, all indicators point to gain-of-function research being useful, I think we should all be able to agree that labs that are not open to being investigated by international, neutral bodies should not be involved in conducting them. The possibility of cover ups is too great.