I can also see also large support for uploading ID to various services when talking about kids, but when you re-frame the question to adults, most seems to really dislike the idea immensely.
Sure there will be children with access to unrestricted devices, just like we had kids with porn mags hidden in a forest somewhere back in the day, or how that one sketchy guy was buying alcohol, etc. But I think this is an acceptable level of risk for whatever harm people want to prevent.
Consider that even with something as divisive as covid lockdowns and vaccines, the overwhelming majority of people complied with government instructions.
There are a minority of people currently refusing to vaccinate their children properly, and their fucking around is being found out with measles outbreaks in various countries.
Why would this be different? Why wouldn't it be a minority of parents permitting their children to drink, to smoke, to use unrestricted computing resources?