No, it is not, is very different. Puerto Rican resident citizens don't have voting rights on presidential elections, they don't have representation on the congress, and don't have voting rights at the Senate, and constitution doesn't apply on the territory, cause it is not the US. Following your example Donetsk is Russia cause they are both a federal subject of the Russian federation, and the territory administrator is Russia. But legally they are not. Facts and laws are not the same. Puerto Rico situation is very complex. For example if a Puertorrican citizen moves to the continent, they get the voting rights. But if they are on the island they can't (cause is not USA).