I'm not a parent and I'm not a fat child any more so why should I care? Because I imagine how much more terrified my parents would have been over my size (I was plump despite their sustained and intense efforts to make me thin) if they believed they could have had their child taken away, instead of "just" being shamed and pressured about having a fat child. Because I imagine what kind of life a fat child taken away from their family and raised in some kind of institution would have.
Although this is just some random doctor sounding off in a random news outlet, and there's no official legislation along these lines as yet, such government sanctioned kidnappings have been happening fairly regularly in the US. As a member of several fat acceptance organizations I hear about one every few months (when the parents seek help from the organization. I wonder how many parents don't seek help from the organization?). Sometimes I find out the outcome and sometimes not.