What about these referendums?
https://en.wikipedia.org/wiki/2012_Puerto_Rican_status_refer...
https://en.wikipedia.org/wiki/2017_Puerto_Rican_status_refer...
Article IV (in part):
New States may be admitted by the Congress into this Union;
...
The Congress shall have Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States;
Too many rich people and politicians benefit from the lack of oversight and low taxes plus the corruption that results for them to allow statehood. If Puerto Ricans are serious about wanting statehood they can stop voting for these corrupt clowns anytime and vote in people that will complete the process of obtaining statehood.
Turnout in the 2012 referendum was 78%.
But on 2012: of 1,878,969 voters, 515,115 (27% of turnout) left the choice between statehood, independence, or free association blank at the behest of the PPD, who’s governor elect immediately asked President Obama to ignore the results due to ambiguity, while the outgoing PNP governor asked President Obama to begin the legislation process.
It’s not even remotely as simplistic as you’re implying by dropping a 78% figure and flitting away without any further context, have the decency to at least read the links you’ve posted.
The Puerto Rican government chose not to pursue statehood based on the low turn out, but the option is still available to them anytime. This has nothing to do with the USA federal government and everything to do with Puerto Rican politics.
Let’s agree that having different classes of citizenship is just a terrible idea for the precious values of freedom, justice, and democracy. No other argument really matters. Working backwards from that, we should eliminate any circumstance in our control that creates any special class of citizen, be they living in gilded cages or rusty iron ones.
EDIT: For the idiots downvoting. I know that Puerto Rico held referendums, I lived there for a while and I know a lot of people in government. The most recent referendum was massively boycotted and got extremely low turn out. Because of this many politicians in Puerto Rico consider it invalid. Bottom line, way too many rich politicians in Puerto Rico benefit from the lack of taxes and oversight to allow statehood. If they want statehood they have to actually put together a delegation to handle the transition which they have NOT done yet.