They saw it as antithetical to the corrupting influence of civilized conformity and the heartless, mechanized, industrialized, materialistic society of the Enlightenment.
As Emerson put it, "the simple genuine self against the whole world" was the movement of the Romanticism, and radical innocence was its essence.
For instance, in the first tale in REALISM: An elastic and ambiguous term with two meanings.
(1) First, it refers generally to any artistic or literary portrayal of life in a faithful, accurate manner, unclouded by false ideals, literary conventions, or misplaced aesthetic glorification and beautification of the world.
It tends to focus as much on the everyday, the mundane, and the normal as events that are extraordinary, exceptional, or extreme. The movement contrasts with (and is often used as an antonym for) literary forms such as the romance, science-fiction, fantasy, magic realism, mythology, surrealistic art, modernism and postmodernism.