Who ensures that LN does not become bitcoins DAO like experience?
That's not really relevant here. Let's all stop any advanced development because an incompetent team failed with their pump & dump coin? I think not. Peer reviews and extensive testing 'ensure' that. Although one can never be 100% sure.
It's a totally relevant! Rather than test LN and its base code SegWit, (bitcoin's DAO), in the real world befor deploying it on a $10B network, why shouldn't SegWit be deployed and tested in the real world on an altcoin before being implemented in Bitcoin?