You left out "unlawful". You are simply trying to dodge the point. If Mr Cruz had remained in Canada, and had been drafted into their army engaged in a war against us, after all was settled, no one in this country would make any objection to Canada for their having used Mr. Cruz in this manner.
Should they do such a thing to you or I, the State Department would consider it a violation of international law, and would likely bring it up as a charge against that Nation.
In Cruz's case, we would recognize the right of Canada to do so. In your or my case, the United States would regard it as a breach of civilized norms, and a crime against the United States.
Stop pretending that there is no difference. There *IS* a difference.
You are incorrect. It is not unlawful as the laws of that nation state allow for it. As to your assertion that it violates international law for a nation state to conscript forces during a time of war, please site the section of law which you think would be violated.
Again, my only assertion is that US law governs US citizenship. You should stop projecting on to my statement anything further than that simple statement of fact.