"insert bunch of convoluted explanations"

I disagree with that description. The explanation seems quite clear, and consistent with my understanding of the history.

"With the exception of Manifest Destiny, the U.S. had always been inward looking ... We ended up with far flung colonies because we kept stumbling into the role of major power. Prior to WWII, the only time we wrestled with the inevitability of our place was with the Monroe Doctrine"

Manifest Destiny is a huge exception - enough to make 'always been inward looking' be meaningless. It helped justify America's own imperialism. Quoting from https://en.wikipedia.org/wiki/Treaty_of_Paris_(1898) , "The U.S. appealed to the principles of Manifest Destiny and expansionism to justify its participation in the war, proclaiming that it was America's fate and its duty to take charge in these overseas nations."

That Wikipedia article cites https://www.loc.gov/teachers/classroommaterials/primarysourc... : "Victory in the Spanish-American War transformed the United States, a former colony, to an imperial power. Many Americans saw this development as a natural part of the nation’s “Manifest Destiny”--the belief that expansion of the United States was both right and inevitable."

We did not "stumble" into paying Spain $20 million for The Philippines. We need only look at the name 'American Anti-Imperialist League' to know that it was a considered decision.

Finally, "As for the pervasive racist beliefs, they had nothing to do with colonialism".

I find it hard to accept that statement without substantial evidence to show that works like:

"Race-Making and Colonial Violence in the U.S. Empire: The
Philippine-American War as Race War" - https://apjjf.org/-Paul_A_-Kramer/1745/article.pdf

"“Racism” and Colonialism: Meanings of Difference
and Ruling Practices in America’s Pacific Empire" - https://www.researchgate.net/profile/Julian_Go/publication/2... . Quoting from it:

> It would seem indisputable that modern colonialism in the early twentieth
century involved racism. ... The historian Partha Chatterjee refers to this as “the rule of colonial difference”—the colonized, by virtue of their biology, were represented “as incorrigibly inferior” (1993, pp. 19, 33). Traditional scholarship has thus treated racism as “a built-in and natural product [of colonialism], essential to the social construction of an otherwise illegitimate and privileged access to property and power” (Stoler 1992, p. 322). More recent scholarship in the humanities has added that the very purpose of colonial discourse was “to construe the colonized as a population of degenerate types on the basis of racial origin; in order to justify conquest” (Bhabha 1994, p. 70). Almost by definition, then, modern colonialism entailed “racism”: ..

That last quote shows that your viewpoint that 'pervasive racist beliefs ... had nothing to do with colonialism' is far from being the majority held position among scholars.

Or as the article says, President William McKinley said that God told him to "educate the Filipinos, and uplift and civilize and Christianize them". How is that not racist?

As another counter-example, why did the US acquire Hawaii? It was not part of the continentalism "Manifest Destiny", nor was it part of the Americas under the Monroe Doctrine.