Didn't we read on this very thread that Cruz not long ago renounced any claim to Canadian citizenship? Have you ever had to do that? I haven't.
Had he not done so, could it not have been due to divided loyalties? What would be so unusual about a person feeling loyalty to TWO countries? It would not be unusual at all for someone whose parents came from different countries.
I've had to explain to people in business over the years many times that having a "conflict of interest" doesn't mean that anybody has done anything wrong. It simply means that they have potentially conflicting benefits from decisions affected by the conflict. That is why "conflicts of interest" must be managed by someone who does not have the conflict; to avoid even the appearance that the conflict played a part in the decision.
Let’s start this by positively affirming that Ted Cruz is not the son of the Queen of England. So, that hypothetical aside, we can proceed.
First, with his father being a naturalized Canadian citizen, Ted Cruz even though he was a citizen of the USA by birth through his mother, also had Canadian citizenship. His parents were working in the oil industry in Canada at the time. They returned to the states when Cruz was 3. He was STILL a citizen of the US by birth.
Second, since Canada was discouraging dual citizenship at the time, and since he was only 3 years old, it is understandable that he did not consider any ties to Canada to be in effect.
Third, Cruz has always been a US citizen by birth. Finding out about a legal claim to Canadian citizenship, he renounced that citizenship simply to do the right thing.
All of that said, none of it matters toward Cruz having been a citizen by birth. He was. He remains so.