I guess I can give a little insight to this conversation, coming from the perspective that I raced an auto first and then a motorcycle.
What’s the difference between racing a motorcycle at a sanctioned and non-sanctioned high speed venue? Hardly any. If I asked the same question about autos, then I could produce a HUGE list of safety items. This is where some of the disparity lies. Also......
While I do agree 110% that a car has no business going 200+ without a cage, I do believe that we error of the side of caution for autos going well under 200. Yes, if you want to run at Bonneville, you need to set your auto by those safety rules and by all means set your vehicle up to the safety standard you feel most conformable. However, an individual that wants to experience what 150 mph feels like in their street driven new Corvette, shouldn’t have to gut it and install all the safety equipment as required by our sanctioned safety rules. Heck folks, I have friends who do road race in the NASA series
http://www.nasaproracing.com/ , who regularly see 175 mph down the long back straightaway at some tracks and they only have 4 point cages. I have attended track days at Road Atlanta where street driven club cars do 150 mph with no cages at all. What do they do about insurance and liability? BTW, you know what happens if you go 150 mph without cage at ECTA? You go home.
Sensibility has to be the key. Yes we need to insure and stress safety, but also need to open the sport up to some lower speed street vehicles . Yes, a turbo Viper running 200 needs to have a bunch of safety equipment, but what about that street driven stock Corvette?