The vast majority of cycling-related head injuries are from falling to the ground, not because a car hits you in the head. The energy absorption required for a 160 lb person falling from 4 feet directly onto their head is only around 1300 foot*pounds which these helmets are quite capable of. In any event, energy absorption is a poor metric for helmet performance since it is rapid deceleration that causes severe brain injury. If the skull decelerates too rapidly, the brain's momentum smacks it against the inside of the skull. A helmet which transfers all the kinetic energy to your head slowly will save your brain better than one that absorbs most of the energy but transmits the rest to your head very quickly.

The decision to wear a helmet is a peronal choice, but I can't imagine your motivation to actively advocate against them.