Agreed. Absolutely no.
Do a little thought experiment. If a child is very short, do the social workers blame the parents? Probably not, but when it comes to weight they assume that parents control the outcome. In a case this extreme, I sincerely doubt it.
That analogy makes no sense. You can’t make yourself taller or shorter by your action or inaction, short of some type of malnutrition or something stunting your growth, in which case social workers certainly would be looking at the parents too.
Also, being short doesn’t in and of itself endanger your life or health. Being grossly obese does.