As you intimate, in some cases its warrented, but you have to have a knowledge of each case to pass a judgement, but here in Essex, this year, there was a case where the mother was a bit slow, (mentally), the father and family helped, she was perfectly capable of looking after the children, and loved them to bits, but they were taken away and put up for adoption, In my opinion, this was wrong, but I personally didn't know the family, only what I read in the paper, so I don't know the intimate details.
But if it was as reported, definately wrong.