> The difference is that in one scenario it’s about punishing something that happened and is done and in the other it’s to prevent ongoing/future harm.

Letting a criminal go free (think serial-murderer, rapist) is just as valid an argument for future harm.

I don't see why you treat these 2 cases differently.

The legal requirements to restraining an individual to prevent some future violence with a known specific potential victim (eg. restraining order, arrest) are lower than the “beyond a reasonable doubt” standard.

The rights of a child to be abused and the rights of a parent to not have their child be taken away are both very important. It’s my subjective impression that the “child abused” case is much more common than the “child taken away where no abuse occurred” case. I see no reason that our laws should be biased in favor of letting that case occur.

There already exists mechanisms to remove people from opportunity to do harm without due process if there is overwhelming, immediate risk. It's very tightly controlled and very temporary. The same could be applied here.

If a child has been living with a mother that (apparently) has 18 drinks a day (getting to 18 drinks a day while still being a functional human is not something you get to overnight, it's a long process) without obviously suffering, this is cause for grave concern, it is a significant risk, but it's not an immediate risk. In this context it's also important to keep in mind that removing a child is possibly the correct answer in many cases, but it hurts the child 100% of the time. That hurt must be less, by a very significant margin, than the hurt of staying put.