This is deliberate. However, just last week, Waymo got the go-ahead to allow their FSD taxis onto highways in Austin.
I have seen varying stats on this, and the numbers can be rigged. For accidents, is it a fender-bender, or does it result in deaths? One can say that only a few accidents are alcohol involved, while most deaths have a high chance of having alcohol as a factor.
Overall, FSD does drive better than people in most circumstances, but it requires a lot of edge case training. It is getting there. I think it is a good thing, because it has faster reactions than a person. There are also things that can be done (provided there is security placed so it can't be hijacked) for V2V communication or V2G which can make easier for autonomous vehicles to navigate and figure out the best lane positioning. FSD also is a good thing for people who don't really want to hang up their car keys because they have to go to work, but are worried about reaction times, and here in the US, the public transportation system is spotty at best.
I'm all for FSD. Just because it always pays attention and has faster reactions.