All of these groups have experience with being subjugated, to some degree, by the US in their own land. Their circumstances have not all been the same, but they do have this general experience in common.
Puerto Ricans are the group that has been most directly subjugated by the United States. In 1898, the US defeated Spain in the Spanish-American War. As part of the treaty that ended that war, Spain gave Puerto Rico to the United States. The island has been US territory ever since. Even though it is US territory and Puerto Ricans have US citizenship, Puerto Ricans on the island do not have the right to vote in US presidential elections and have no voting representatives in Congress. Thus, their land has been taken by the US without actually becoming an equal part of the country.
Mexico is the country that has been least directly subjugated by the US. Of course, the US did take a large portion of Mexico’s territory after it won the Mexican-American War in the 1840s. We can say that this is part of Mexicans’ experience with the US in their own country. However, the US never directly controlled Mexico itself. Instead, the US has had something of a neocolonial relationship with Mexico. Mexico has needed America’s business so badly that the US has had a great deal of power in that country. The US’s economic power has allowed it to have a great deal of influence in Mexico, leading many Mexicans to resent American power.
Cuba falls somewhere in between. In the Spanish-American War, the US freed Cuba from Spanish rule. However, it then proceeded to pass laws that allowed it to maintain control over Cuba. It gave Cuba self-government, but retained the right to control Cuba’s relations with other countries. As with Mexico, Cuba needed American business and so America had a tremendous amount of influence over Cuban governments up until Fidel Castro’s revolution in 1959.
In these ways, all of these peoples have experienced subjugation and domination by the US in their own lands. The US has had varying degrees of control over the three lands, but it has been very influential in all of them, having a great deal of power to coerce even the leaders of the lands it did not actually control.