I believe the point Nik is making is that the FIA, the international sanctioning body for cars, did their own independent testing on the HANS device and agreed that it significantly reduced injuries for drivers and was safer. Therefor they implemented it in the racing series under their control.
The CIK-FIA, the branch of the FIA that oversees kart competitions, did similar independent testing with neck braces seen in karting. Their determination was that the braces did not significantly change the rate or severity of injuries in kart crashes, and as such did not mandate them for their events.
A company doing their own research into the effectiveness of a product is great, and expected, but independent test results are also very important in confirming that the results found by a manufacturer are correct.
Your comment about holding the head up is interesting to me. I never experienced issues with having to hold my head up in a race, and I believe it was said somewhere else that if the brace is in contact with the helmet like that, it actually provides a point that the helmet can rotate around that isn’t central to the neck and cause strain on muscles, tendons, and possibly even vertebrae in the neck if there is a side impact with the kart. Does your design look at that factor in the brace? What testing specifically have you done for the development in your product?