There is more to the story.
"The mother, in her 20s, suffered from minor mental health problems and other difficulties and the father had in the past been aggressive to others."
I'd wonder what the other difficulties were. I think the minor mental health problems would not have a significant impact, IMHO.
"But staff at the special care baby unit where he was cared for in the days after his delivery had expressed 'no child protection concerns'."
They only saw the couple over a few days though.
"Maternity ward medics did, however, tell the council they were anxious about the couple's long-term ability to care for their baby."
So there is a discrepancy between the staff and the medics, but they were presumably all people who had only known the couple/family a short time?
"Among other things, they said the father had 'expressed unorthodox views about the need for sterilisation of bottles and the benefits of formula milk.'"
So it was not just about using formula but about sterilizing bottles.
I don't think we have the full story here. I am not saying social workers never make mistakes, I am sure they do sometimes. But I think on the whole taking children into care is quite a major thing and the generally parents are given a lot of opportunities to succeed or fail before the child is taken away.