Originally Posted by nun
the US way of gaining citizenship and taxing based on citizenship is really dumb.
I agree with you that the US way of taxing based on citizenship is really dumbd.
However, the principle of citizenship based on location of birth goes back a long way. There are 2 basic citizenship principles
jus solis (by virtue of birth at a location)
jus sanguinis (by virtue of 'blood'--who you were born to)
Much of these date back to the time of Caeser. Most countries use some combination of these (e.g. Germany doesn't necessarily confer citizenship if you were born in Germany unless you are "German.")
The reason that the parents cannot renounce a child's citizenship for him is that this would be a violation of the UN Treaty on the Rights of the Child, which prevents a person's (even a child's) nationality from being stripped from them due to the decision of another without due process and without their consent. Since they are not old enough to consent, it must wait until the age of majority, unless there was fraud or some other reason for a hearing.
I can tell you that this is a good rule. It leads to absurdities here, but those absurdities relate to stupid tax policies. This rule was violated in my case (my Canadian citizenship was illegally stripped from me as a child, and not even deliberately). It took me many years and a lot of trouble (and literally an act of Parliament) to get it back. Besides, at age 18, the person may decide that having dual citizenship is worth the extra bother.