Imagine you're following - at a safe distance - a vehicle. The driver of the vehicle you're following doesn't notice that the car ahead of them is emergency braking. They notice at the last second and swerve around it to avoid a collision.
You are then face to face with a nearly-stationary object which was concealed from you by the vehicle ahead of you.
From your perspective, it fell from the sky. If you don't swerve, a collision is unavoidable.
I think we are in agreement with the the situation, I just disagree and think you're either driving too fast or following too close. Your logic leads to pile ups, as in the event of a pile up, a car stops dead unexpectedly infront of you and you have nowhere to swerve.
I can't speak for the USA, but in the UK, if someone swerves and you rear end a stationary object, you are at fault. Indeed if you rear end another vehicle, you are nearly always at fault (unless e.g. they pulled in front of you then immediately slammed the brakes).
Stopping distance at 70mph is about 100m and "The safe rule is never to get closer than the overall stopping distance". This is a minimum - in adverse conditions the distance should be even greater.
This means when you see the stationary object, you're about 100m away, which is adequate time to stop IF you're paying attention and your car is well maintained (we have annual MOTs to ensure this).
Maybe there truly wasn't enough time to completely avoid a crash. But there should have been enough time to avoid a serious (deadly) crash.