If your life is not your own, to do with as you please, then you are a slave. I'm happy for this couple, they seem like exactly the kind of people who get the most benefit out of this choice.
You've come out very aggressive. How do you interpret their comment?
For me, the comment was saying that their lives had become ruled by pain (in Ils case) and Jan's impending dementia. Under these circumstances, it was the kindest thing to both of them to allow them to die.