It is the companies, not the FAA. They don’t want to be sued into non existence.
An experimental aircraft is ‘experimental and the person that put what ever they wanted to experiment with… is responsible for the end result.
You can go to the hardware store and use whatever they have there to put on your plane, and in the end, YOU are responsible for what happens if you crash.
That is why experimental aircraft have cool stuff. No liability tied to the company that made it.