Answer:
Roosevelt's campaign was based around colonial expansion and the Spanish-American Civil War, where he saw service and commandeered with a Calvary unit known as the "Rough Riders". He referred to his service as a main talking point in many of his speeches and exploited it to win the campaign. If there was a view that Imperialism was morally corrupt back 'then', his popularity would've never took off as he figure-headed as a war hero for an imperialistic, colonial war.
