The first gives patients and families more options in how to deal with end of life care, the other takes options away.
Yes, it takes it out of the hands of the family and actually respects the patients final wishes, that they made for themselves while still lucid.
Of course (unfortunately) most people still don't take these steps to make their wishes known. But the original comment was about "laws preventing family members from prolonging the suffering of their loved ones," specifically about an example of a young child, whose wishes were not known (and of course not really relevant for a toddler). The fact is in the absence of any advanced directive I would much rather have the family make decisions about the type of care desired by the patient than the state.
A lot of small towns in Alberta only have Catholic hospitals (which are publicly funded, but run by Covenant Health [0], a Catholic institution). They refuse to provide, among other things, assisted suicide or abortion services despite being publicly funded. 4/9 of Edmonton's hospitals are run by Covenant Health.
[0]: https://en.wikipedia.org/wiki/Covenant_Health_(Alberta)