There is far less moral hazard as a general aviation pilot because death/grave injury is far more likely in an airplane collision, whereas a personal vehicle driver is relatively safe, especially in vehicles most dangerous to others
Regardless, what is and is not required of all pilots is beside the point. The point is society implements a safety/accountability measure to prevent x rate of injuries/deaths…but society does not implement the same safety/accountability measure to prevent y rate of injuries/deaths where y is far greater than x.
The discrepancy is because it is politically unpopular to hold the people causing the larger rate of injury accountable (voters who drive personal cars), whereas it is politically popular to hold the people causing a smaller rate of injury accountable (commercial pilots).