I think the debate around helmets is beside the point. Why? Because it's not really up for debate that helmets prevent brain injuries.
If danger from road users increase because of wearing a helmet, that's an issue with the drivers and the non-separated infrastructure.
As a daily commuter riding a bike, I say we keep the helmets. It's like wearing a seat belt and should be mandatory as long as we have a semblance of socialised healthcare.