I think the argument is: While a sane/rational person will stop, you are still risking your health. You're doing something unexpected (Like the idiot in the YT video).

The premise is that self driving cars will and can react defensively. While someone driving home after a long day in the office might not.

So - yes, you can abuse human drivers, today. But the GP seems to think that it's far more risky now and will be ~trivial~ given good enough self driving cars.