For those who like facts, start at the beginning. Bicycle helmet safety standards and stats from federal agencies. I haven't seen these posted recently, so during this lull in the flame war I thought I'd post a few links.

A Comparison of Bicycle Helmet Standards summarizes a bunch of the different standards

1995 STANDARD FOR PROTECTIVE HEADGEAR For Use With Bicycles detailed Snell Standard

2015 STANDARD FOR PROTECTIVE HEADGEAR For Use with Motorcycles and Other Motorized Vehicles if you really want to compare with motorcycle helmets.

Bicycle Helmet Safety Institute Bicycle Helmets for the 2015 Season a LOT of information about current helmets

Injury Prevention & Control: Traumatic Brain Injury links to TBI related data and statistics from the CDC

TRAFFIC SAFETY FACTS 2012 Data National Highway Traffic and Safety Administration, injury and fatality statistics for bicycling.

FARS data tables, Pedalcyclists from NHTSA detailed fatality stats.

Enjoy.