Puerto Rico is a colony of the United States, and the purpose of a colonial relationship isn't for the imperial power to aid the colony. That's sometimes a side effect, but the intent is for benefit to flow the other way.
If Puerto Rico were part of, rather than a territory subject to, the United States, they would have representation in both houses of Congress and in the Electoral College.
No relationship is one sided - it takes two to make it a relationship.
The US doesn't need Puerto Rico - Puerto Rico needs the US.
The US didn't “find” it, it took it by force.
EDIT: From another colonial power. I’m not sure Spain is really in the market for a Carribean colony right now, so it might not be that easy for the US to walk away and leave PR in its pre-US position.
Well, we do let them have one non-voting representative in the House (similar to D.C. and other territories.)
That 1812 Constitution of Spain was a product of the Napoleonic wars and seems to have been basically ignored everywhere but Iberia-proper. So really, PR has never had proper representation to its colonial rulers. And technically PR has had a non-voting rep. in the US house of representatives since 1901.
If anyone wants more info on the topic, John Oliver has a great, 13-min segment on U.S. territories along with the clearly-evil justifications for their situation. Wait till yall see the Supreme Court ruling. It should get way more attention in media discussions on this topic. His finale with America's Got Talent contestant is also an epic counter to that.
But, yes, it was a deliberate choice in the Constitution that the capital district would be a subject territory, a decision which was partially walked back only fairly recently by the 23rd Amendment.
They are U.S. citizens. It is a U.S. territory. They are required to follow U.S. Federal law, yet do not have representation within the U.S. government. Even if they were not U.S. citizens, since they are not autonomous and allowed to govern themselves entirely, the U.S. has some responsibility over any situation Puerto Rico finds itself in.
If you think they should be paying income taxes, tell your congressperson to stop dragging their feet and respond to the requests for statehood Puerto Rico's government has made multiple times.