Parent here, responding from my perspective. I say these things, but I believe that what it means (to me) is I would do anything for my child to live a full, happy, healthy life. I want them to be good people.
In the face of danger or struggle, I would do anything to help them. I will love them unconditionally, but that does not mean I will accept or excuse poor behavior from them; it means I DO hold them accountable for their actions because I believe in their goodness and ability to be functional, good, moral humans. Love is not blind, IMHO.
I can't know what these parents' experience of their kid coming home was, but I guarantee you that if my child was in this situation I would not be enabling them in any way. Supporting them to find a lawyer and mental health team? Probably. That's my job because I raised them and whatever problems they have/cause I share responsibility in (to a degree). But what the Laundrie's appear to be doing is not normal parenting, and it's not even love if you ask me.
Eta: I often tell my littles "I love you too much to allow you to behave this way," and I feel like that explains what I'm getting at here.