How many children were removed in your state last year? How many in the country? - when there wasn't any criminal conviction of abuse of a child. In other words, how many children are removed from their homes just to obtain federal funds? How many are removed because a social worker likes playing God?
You may ask; "What about the parent who is using illegal drugs?" In most cases children are still better off with their own parents. University of Florida researchers studied two groups of infants with cocaine in their systems. One group was placed in foster care, the other with birth mothers able to care for them. After six months, the babies were tested using all the usual measures of infant development: rolling over, sitting up, reaching out, etc.
Consistently, the children placed with their birth mothers did better. For the foster children, being taken from their mothers was more toxic than the cocaine. It is extremely difficult to take a swing at "bad parents" without the blow landing on their children.
In a different context but fitting here nicely, Jesus said "Do not pull up the tares (weeds) lest, while ye gather up the tares ye root up the wheat with them."