My biggest problem with PR becoming a state is not political but cultural. Take Hawaii as an example of what imposed US rule will do to the heritage and history of a country.
This next part is copy pasta but well stated. This is the exact message I received as a child growing up in PR.
"The US has treated Puerto Rico as little more than a colony for 100 years, and this has seeped into the Puerto Rican mentality in harmful ways. According to educational scientists Francesco Cordasco and Eugene Bucchioni, in their 1973 work The Puerto Rican Experience: a Sociological Sourcebook, the belief that Puerto Rico cannot survive on its own results from teachings since grade school. “Puerto Ricans here and in Puerto Rico are taught three things: Puerto Rico is small and the US is big, Puerto Rico is poor and the US is rich, Puerto Rico is weak and the US is strong.”
Popular author and Puerto Rican culture enthusiast Jesús Omar Rivera similarly argues that “in Puerto Rico, ever since you are a child, you are told that you live on a tiny island that has no natural resources, nothing. This is what they teach you in school, on TV, the media, and it’s always negative.” He argues says this perception is a by-product of the island’s political dependence on the U.S.. “There is this colonized mentality that everything from abroad is better.” None of this would change under statehood, and arguably would get even worse as Puerto Rican culture, still perceived as 'inferior' to all things American, would decline even further.
Historically speaking, and a point to my Stockholm Syndrome reference earlier, the US has quelled numerous attempts to overthrow US rule in PR since invading the island in 1898. Over time, Puerto Ricans realized that we obviously couldn't do anything about the occupation (US is so big and strong and we are a tiny island nation) so the populous decided to just make the best of it by approving commonwealth status in the 50's. Eventually that lead to a dependence on the US that has lead the population to believe that we simply could not stand on our own without the US.
The thought that the US magnanimously granted Puerto Ricans, conditional, citizenship via the Jones act of 1917 in order to help a poor and downtrodden people is ridiculous. The Jones act allowed for Puerto Ricans, despite their inability to elect a president, to be drafted. 20k Puerto Rican soldiers were immediately conscripted and sent to fight a war on behalf of a nation that only 20 years earlier had invaded their home land.