I assume this applies to children of illegal immigrants, not just those who overstay visas??
in any case, the child should not be punished by what "adults" have done to control said child's world.
If the children are
returned to their country of citizenship, they are not being punished for what adults have done. They are living with the consequences of what has been done to them.
If a man robs a bank and is sent to prison, do the children get to keep the money? Or do the children have to live with the consequences of having their father sent to prison?
When a person does something evil or breaks a law, others often--almost always--live with the consequences of those actions. Children
always live with the consequences of their parents' actions.
Either the U.S. has laws governing immigration or the U.S. should just let anyone in who wants to live in the country. If the U.S. is going to restrict immigration, the laws in place should be followed.