"Let's not demonize the Nazi, didn't you know he undertook the arduous and benevolent task of creating a special category just for those of you that were exploitable for your labour? Sure he had a bunch of you exterminated but he sterilized and saved some for work and that should count for something."
Utterly repugnant worldview. If at any point you find yourself coming up with reasons to defend a Nazi, and you don't take a moment to look at yourself in the mirror and ask yourself what the fuck you're doing, you're failing as a human.
Someone who actively participated in the mass murder of children might have redeeming qualities (and I'd argue the one you think you're highlighting isn't one at all), but none of them will ever outweigh the fact that they are monstrously inhuman.
Do you have any idea how profoundly his work has negatively impacted every autistic person since? We're still trying to excise all the fucked up useless gendered concepts his perspective injected into the diagnostics. The notions that we lack empathy, have some kind of extreme "male intellect" and/or psychopathy, that the way we're born is some kind of defect in humanity that must be studied and purged, that's his legacy.
He was one of the first to try to identify and categorize us, not out of altruism, but because he saw us as a diseased branch of humanity that was situationally useful but ultimately unworthy of life. If that's not worthy of demonization then I don't know what is.
It doesn't have to be a kill list, that's what you're not understanding. Medicalizing dissent, creating registries of potential scapegoats and vulnerable people to target or practice on, that's the purpose. They create an outsider group to stigmatize and then broaden the definition as necessary.
You need to look at this step within the totality of the conduct of the regime so far. They are already rolling back child labour laws and openly talking about the need for a baby boom. Children are one of the most vulnerable groups in society, especially in conjunction with other factors like a migrant background or being in foster care. How many kids are in precarious situations with either absent or completely disempowered parents?
They're already putting unattended children in front of immigration judges without legal representation, if the state simply kidnaps and disappears the children of people it's trying to deport without due process, what's to stop them? What do you think these ghouls might want to do with lists of kids?
What you need to recognize is that this is the sort of registry that would be directly accessible by those surveillance initiatives you mentioned. It's not duplicated effort, it's part of the same effort, this is just one of the ways they are trying to define their enemies and undesirables.