It is actually very easy to understand. Cruz is not NBC and not qualified to be POTUS. Canada maybe, but not the US.
Can you cite any serious legal authority who agrees with you?
If like our Constitution, Canada’s says you have to reside there for 14 years to be President, then, no, he was never qualified to be President of Canada.
Cruz is a natural-born U.S. citizen. Did he have to immigrate here? No, he was a citizen at birth. Our Constitution wasn’t so stupidly written that it didn’t make children of U.S. citizens natural-born citizens themselves. It would be hard to raise your child if you couldn’t bring it back into the U.S. if it was born while you were traveling abroad.