To hit the 100% number you would have to prematurely kill many people that die peacefully but unexpectedly, and then forcibly kill many people who want to die naturally.
But supposing we were to live in a ideal world, we'd wish it to be so that every death that occurs happened by the wish of the deceased, in the best comfort that can be offered to them.
They said “ medically assisted deaths should be 100%”, not that everyone should have full control and choice. This is a very different point. The former takes what a personal preference to be a universal value, and supposes that an ideal world would conform the their preference, not just have choice.
I'm not sure what position you're ascribing to them, that we should have everyone killed by doctors at birth? I mean that could work if interpretated literally for the stated case, but who in their right mind would believe that?