I suppose what you’re saying is true, in the same sense that using any modern computer technology which has software in it’s stack, which hasn’t been formally verified, is fundamentally unsafe.
If an IDE on your laptop malfunctions, you end up with a crash or some malformed data.
If self-driving fails, you end up barreling down the road in a 2 tonne deathbox, likely killing you or someone else.
Not equivalent in the slightest.
By your own argument all adaptive cruise control is unsafe. Maybe you think the manual and warnings given to the consumer qualify "defining any operational domain where it can operate safely", but it doesn't give an exhaustive list of "here's where you can safely operate this", it just says to not use it when it's unsafe to do so - it's always "drive safely and take control when necessary" because the scenarios are literally infinite.
I guess you might not be getting scammed if you know it is unfit for any purpose, but at the very least you are being a danger to society for using a explicitly unsafe product that can not be operated safely.