I can see both sides to this argument, but in reality on a bike tho ONLY protection you have is the protection you wear. In a car you have so much more, crumple zones, air bags, suspension etc. etc.
I would rather have a car crash at 60km/hr than a bike crash at 20km/hr - my money would be on the car driver beeing better off.
I think a $25 pushbike helmet on a car driver would probably make them safer than any armour you could get on a motor bike rider.
At the end of the day its about taking risks, and if you dont like the risk, dont take the car on the track.
Ruben, your comment that "I have crashed numerous times on track at over 130+ kph. I get up and walk away" is probably a better argument for the safety of the track than the helmet, what do you think your chances would have been like if you did that on the road? My guess is that your head may not be crushed, but is still unlikely to be attached to your body. Falling off a bike at speed isnt fun, but its usually what you hit next (or what hits you) that causes the damage, and cars, gutters, trees, stoby poles etc are never rider friendly.