To add to what /u/b1uepenguin said, you have to remember that the term 'colony' was very loaded for an ex-colony like the US. The new paradigm was one of indirect control, where possible. I'm not an expert in the period of the Spanish American War, but renowned historian Robert May wrote in the epilogue to his book Southern Dreams of a Caribbean Empire (1854-1861) that after the American Civil War, projects to expand the US territorially gave way to projects to dominate commercially and through indirect means.

The basic colonial project the US had was to 'civilize' the Spanish and non-European races it had come to dominate with the goal of then controlling them indirectly, thus saving themselves from the costs and problems of direct government and avoiding the uncomfortable idea that the US had or would become a colonial power just like Great Britain.

Thanks to numerous factors, in particular the Teller Amendment, which forswore direct US control of Cuba, Washington had to create a special solution to control of the island. This was found through the imposition, by the military governor Leonard Wood, of the Platt Amendment upon the Cuban constitutional assembly, which allowed the US to intervene whenever, wherever, and for however long Washington saw fit. The US also imposed on Cuba the sale of key military sites, including Guantanamo (which it still holds today), to serve as refueling stations for coal based steam powered warships that projected American power into South America back in the days of 'gunboat diplomacy'. This meant that Cuba came out of the war officially a free republic but, in reality, with severe limitations on its national sovereignty. The Platt amendment would not be repealed until the Revolution of 1933.

Cuban historians, even before the Left wing 1959 Revolution, saw this as an imposition and the change of one colonial master for another, though with less obvious chains, and have dubbed the period between formal independence in 1902 and the 1933 Revolution as the 'neo-colonial period'.

While de juris (legally speaking) none of these territories were formally colonized nations, I definitely think that solid arguments can be made that they were de facto (in actual fact) colonies, whatever niceties were used to denominate them formally. However, given that a great deal of American political ideology and identity sees the country's role as a purveyor of freedom and a nation which resists the colonialist powers of Europe, it is unlikely that even in hindsight many Americans wish to see our intervention in these countries as anything other than paternalistic benefactors.

Some interesting books which deal with the issues I mentioned:

Robert E. May: Southern Dreams of a Caribbean Empire, 1854-1861.

Lars Schoultz: That Infernal Little Cuban Republic.

Louis Perez Jr.: Cuba in the American Imagination: Metaphor and the Imperial Ethos

Those are just words. It seems to be, the problem might be parsing the difference between colonialism and colony- and how liberally those terms are deployed. Colonialism certainly doesn't require the official label of colony for it to operate- which was never a big part of American descriptions of American territorial claims outside of the continent

US colonialism was and is a real thing in the Philippines and elsewhere in the South Pacific. But the term 'colony' is almost never used. Consider Guam, which was claimed at the same time as the Philippines, and saw much larger demographic and cultural shifts as the result of being claimed by the US- it was never considered a colony- but a Naval station- an island governed by a Naval governor.

Hawaii as well was never considered a colony- but became a territory after annexation- and is now a state/occupied territory (depends on ones politics).

Nor was the Federated States of Micronesia, Palau, the Marshall Islands, or the Marianas considered 'colonies' though we can definitely say that US colonialism operated and continue to operate in those nations.

To some extent its all just words though. Whether you chose to call any of those places an American colony or not depends on your own politics. As I said, few Americans are going to call those places colonies- or even be aware of the nation's former (and often) continuing presence in those nations. Yet, those who live in those places, especially activists, are very likely to talk about being occupied- about being a colony. There is a definitely a semantic divide between what we chose call things and what was might want to call them. Just because something wasn't called a colony, doesn't mean it can't still fit the definition of a colony.

I'm pretty sure it was the comedian George Carlin who has a great piece about white-washing terms so that they become meaningless. A thought worth keeping in mind when we consider government or textbook labels and take them for natural or neutral ways of describing things.