You are incorrect regarding the child would have been absolutely deported if both parents are illegal aliens. I am not an immigration attorney, but I have prepared, filed documents and represented dozens of natural born citizen children in guardianship/conservatorship proceedings in state court to allow them to stay in the U.S. with 3rd parties (usually family or friends) when their illegal alien parents are being deported. This is very common for children over ten years of age. I have also prepared the documents which allow children who left with their parents when young and wish to return to and live and attend school in the U.S. Similar to Obamas situation. Although I have never looked into it, I would guess that his GPs needed some sort of guardianship document to register him in school or to authorize medical treatment while he was a minor living with them. People like their answers in black and white. There is something about "yes" and "no" that comforts the mind. However, the real world works in probabilities and percentages, and there is seldom solid demarcations. With that in mind, it is my custom (as it is most people) to characterize the most likely probabilities as certainties, and the least likely probabilities as irrelevancies.
Unless you can demonstrate that your above described circumstance occurs in the majority of cases, I have no interest in arguing your point. Also, postulating a support structure sans parents (especially regarding infants) is not a reasonable assumption. I certainly would have no such support structure in Mexico were the situation reversed.
Another issue with your post is that there is legally no such thing as a de facto deportation. Do you have a statutory or case law citation to back you up for your statement?
You apparently do not comprehend the meaning of the term De Facto. It is by definition, not subject to case law or citation.
"De facto (English pronunciation: /diː ˈfæktoʊ/, /deɪ/[1]) is a Latin expression that means "by [the] fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." "
Unfortunately you are confused about deportation law. Your nonsense about percentages and probabilities is just avoidance of the issue and facts I have presented to the discussion. I deal with real life decisions for people in in a difficult situation. What I have described is fairly common here in Texas. The theory you are pushing that citizen children must be deported if their alien parents are deported is a falsehood. You can close your eyes to the real world, but that does not change the rule of law in this country.