There's an old saying that "aviation regulations are written in blood". If there's an FAA rule it most likely came about from the learning of an accident investigation.
If I had a nickle for every time some dolt busted out the "written in blood" quip for a rule that had no blood involved I'd be a very rich man.
Lots and lots and lots of rules, especially post 1970 or so are about ass-covering. Post 1980 you get a lot of rules designed to remove human judgement from the equation.
