Parents are already allowed to restrict their children access to 'dangerous' things like open computers or knives.
I don't think debazel was saying that children should have been banned from owning computers for the benefit of the children. He was saying that children should have been banned from owning computers so that the government would have no excuse to regulate what's allowed on computers.
Parents are also allowed to restrict their children access to alcohol and cigarettes, but it seems a government ban on them buying those things works better