Why did supporters of Manifest Destiny argue that US expansionism was not imperialism?

Supporters of Manifest Destiny argued that U.S. expansionism was not Imperialism because they believed it was a divine right and duty to spread democracy and civilization across North America. They viewed the expansion as a way to promote liberty and progress, rather than subjugating foreign peoples. Advocates contended that the expansion would benefit both the U.S. and the territories acquired, fostering economic growth and cultural exchange instead of imperial domination. This perspective framed expansion as a moral obligation rather than a quest for power or territory for its own sake.