THAT IS THE LAW. You are missing the point repeatedly--maybe on purpose. The issue is the definition of NBC and eligibility to be President under the Constitution. The courts have never ruled on what the definition means.
Yes, Cruz received his American citizenship thru his Amcit mother. The US-born children of illegal aliens, green card holders, and tourists receive their American citizenship thru birthright citizenship. The criterion that if you do not require naturalization then you are a NBC means that all of these children are eligible to be President. It is specious and has not been tested in the courts.
Do you believe that the US born children of illegal aliens, tourists, and green card holders are eligible to be President under the Constitution?
Have you read the Tribe/Olson Natural Citizen memo?
As someone who has professional and personal experience with this issue, I would like to see this issue decided sooner rather than later by the courts. It has never been adjudicated.