[The Blue Angel is important because it so presciently shows the immaturity and sadism of the German middle class.] In its singular contemplation of the sudden disintegration of a pillar of bourgeois society under the quick, corrosive influence of a strong application of gutter sex, it starkly reveals the imperfection and fraudulence of the facade of middle-class decency and discipline that its ponderous hero represents. It sourly suggests the soggy culture out of which Nazism oozed. And in the sadistic frenzy of the schoolboys to torment and destroy their hated teacher after they have witnessed his weakness for the cabaret girl, we may spot the incipient viciousness of later Hitler Youth.
But I find The Blue Angel most engrossing because of the opening it makes upon the whole darksome, subterranean area of psychoneurotic sex. Where the custom in silent pictures was simply to treat the primal urge as a powerful but usually unholy and sinful appetite that overwhelms men and women by its sheer physical rush and urgency, the revelation in this picture is a sickly image of sex as a passion mixed up with deep obsessions to dominate and get revenge. And where the evil of it in the silents was mainly its immorality, the evil of it in The Blue Angel is its corruption into a social disease that infects the aggressions of people and causes them to act in debased and vicious ways. (pp. 71-2)
It is notable that Stemberg does not give us any scenes of Rath and Lola making love, none of the sort of erotic acrobatics that have shown up in later sex-charged films. This is tremendously important, for it is all too suggestively implied in the few shots he shows of the teacher fumbling clumsily and grossly with the slut that any sex act between them would be disgustingly callow and crude, totally without pleasure for either of them. This leads us back to the premise that it is sex in its more neurotic form that is the essence of this picture. (pp. 75-6)
Bosley Crowther, "'The Blue Angel'," in his The Great Films: Fifty Golden Years of Motion Pictures (copyright © 1967 by Bosley Crowther), G. P. Putnam's Sons, 1967, pp. 71-6.