Please acknowledge that, and tell us if you will be consistent in your thinking and demand alcohol etc. be made illegal.

Furthermore:

The world sucks. Lots of children have rotten parents, and most of them aren't rotten because they use drugs. Many of us grew up with rotten parents. Astonishingly, most of us who did, still love their parents and are grateful the state didn't intervene. In most cases, having child services snatch the child away from the rotten parents will only make things worse for the child.

You "regulate" the cocaine user when they behave in a way that attracts justified interest from the authorities.

Or do you think it would be better if the government had preemptive surveillance measures for every house, to make sure no parents are doing cocaine, and to seize the children preemptively soon as it appears to be so?

Anyway, what you're saying bullshit. The state is not currently using the fact that cocaine is illegal to save any children. That's not the reason cocaine is illegal, and making it illegal has fucked up many more children than it has helped. (In other words: show me empirical evidence for your outlandish implied claim that prohibition is good for children, or give up on it.)