I don't think riders need extremely loud exhausts to be safe, but an exhaust sound adds an element of safety that cannot be ignored. It's the same reason why all vehicles are fitted with horns, after all.

I think people might be more understanding if they rode a motorcycle in a busy city for a few months, and realised how many drivers (at least in my city, London) are far too busy looking at Facebook to drive.

Driverless cars can't come soon enough; though I'm sure that road will lead to motorcycles being made illegal anyway - but that's another story...