Maybe synthetic, since it a synthesized chemical rather than a refined.
But honestly that's not really better, because synthesized is not inherently bad either.

I think what he meant was that these sugar substitutes are not natural to have in the amount possible with industrialized food.
But then again, the exact same thing goes for sugar.

There is no obvious argument IMO why sorbitol or any other alternative sweetener would be harmful.
And it is still far from certain that even if sorbitol can cause liver disease, that it is MORE harmful than sugar, that we know can cause a long range of diseases like diabetes and heart attacks.

Nothing is safe if you take high enough volumes of it. If you drink 5 liters of water quickly, it can cause brain swelling, and you can die from that too. And water is probably the least harmful substance you can take.

My conclusion is that the "point" is simply wrong, even when being as charitable as you can possibly be.