The reason that law was implemented was to recognize the states duty to the offspring of the people of the nation. Do you really think the framers of the 14th amendment would agree with loopholes like “anchor babies”? Of course not, because while they were born here, the intent behind the 14th was to grant immediate citizenship to the offspring of the people who built the country. This is what I mean. Anchor babies were an unforeseen flaw.
It’s not arbitrary. You think it’s arbitrary because you have the impression that the US is just some economic zone with a basket of benefits. ITS NOT. We’re a nation of people. The nation and its people have no obligation to you or any other non member of the people. YOU ARE NOT ENTITLED TO IT. Why do you think you deserve citizenship? You think so because it would benefit you, not thinking for a second whether you’d benefit the nation or it’s people.
Given that you view the country this way, you don’t deserve it either. We’re not a basket of benefits to be plundered by the whole world.
The duty of the nation is to its people and them alone. Immigrants come only if they are a benefit to the people and the people want them. The state acts on behalf of the people in this mission.