Earlier quoted context omitted.
Why not use the fabled "lightning network" layer as layer 1 if it functions as it should? Is it not just a blockchain slapped on top of the slower blockchain?
The lightning network has no security (protection against double spend) on it's own. It relies on the underlying blockchain for that.
That's not true. By locking funds into a Lightning Network payment channel you solve the double spend problem _in the channel_ (the person receiving your payment knows that in order for you to double spend the channel, the payment recipient would need to approve the double spend). The risk of being double spent still exists on the underlying blockchain though, which is solved with a smart-contract structure that allows the counter party to the perpetrator of fraud to revoke a fraudulent double spend.