If 20% or more of caregivers are CPS, then CPS does less harm to children than parents (using the numbers you provide). Since this is not the case, no matter how you feel about the facts, the fact remains that CPS does more harm than good. Children are not more at risk from their parents, and only the fact that CPS is prevented from having more kids enables you to cite figures that show CPS doing less harm overall.

"...children suffer a higher ration of harm in foster care because there are less foster homes."

It is not because there are less children in foster homes that foster children suffer higher rates of harm. It is because there are fewer children in foster care that children suffer lower rates of harm - because parents harm them less than foster care. The rate of harm is higher in foster care, and the total numbers of children harmed would rise proportional to the rise in the numbers of children in foster care.

If equal numbers of children were in foster care and under parental care, far more children would be harmed. The few studies that show relative rates of harm show that foster care is ten times more harmful than parental care. If there were 100 children and half were in foster care, 10 or more children in foster care would be harmed, while 1 or 2 would be harmed by their parents. Were there no CPS involvement the number of children harmed would be 2 or 3, versus 11 or 12 with CPS involved. If only CPS cared for children more than 20 would be harmed. The more children that get sucked into CPS, the more children are harmed. That is why the sources you cite do not reveal this data.

Your assertion that children are more at risk from their parents seems to result from your personal experience, which is not statistically relevant, and your inability or refusal to acknowledge the data that shows foster care is ten times more harmful to children than parents. No matter how I try to explain you do not acknowledge this data. It is not going to be useful to continue this discussion because the data is the key to understanding, and you do not acknowledge the relevance of the data.