Not so. I make no assertion as to Bellei, but as to Cruz, he was most definitely a US Citizen at birth and not merely because of some statute. He was a citizen at birth because his citizenship derived naturally from the circumstances of his birth so that there was and is a natural and abiding connection between the him and the society and nation into which he or she is born. That's it, like it or not, argue till the cows come home and on into the night, you won't change a thing. Ted Cruz is a US natural born citizen and no court or body of any kind with jurisdiction over the matter will ever rule differently, because this is the law.
It's total nonsense to reach no conclusion as to Bellei, and simultaneously make one as to Cruz. Both were born of US citizen mothers, alien fathers, and born abroad. If Cruz is a citizen without resort to a statute, then so was Bellei. But that isn't the case, and you know it.
You are just making things up. SCOTUS has labeled persons born abroad to one citizen parent as "naturalized." There are zero precedents to the contrary, and thousands of citizenship cases that apply the rule of law stated in Bellei, WKA, Miller v. Albright, etc. Courts rule thusly on a regular basis. That they don;t take a case when the subject is a presidential candidate is fecklessness on the part of the court system.