Aesthetically unimpeachable--it's basically the equivalent of watching cinema learn how to walk by sprinting into a full gallop, and it feels contemporary even 90+ years hence--but it also reminded me of "Goodbye Earl" by the Chicks. 

Stay with me here. 

"Goodbye Earl" is a song about solidarity and responsibility for the other as not only the best way toward justice but the only way, particularly in a modern world that lends itself so easily to the anonymizing forces of capitalism and the apathy of a surveillance state. It exhorts us--the rollicking rhythm, almost wish-fulfillment lyrics--towards an ethos of caring for each other, looking out for one another, particularly amid systems that were ostensibly designed to do the same but do anything but. 

M has the same basic exhortation, but layers it with an astute cynicism about how difficult it is to achieve it at scale. Communal justice is the solution here too, despite Lang's deliberate and painstaking efforts to depict an almost technocratic Berlin. But there is also a cautiousness here as well, as Lang notes how easily this communal justice can slip into relinquishing the axe to strong men masking their abuses of power as "the cost of doing business", not to dissuade us from looking out for each other, but to remind us the moral choice (which is to say, the decision of whether something is right or wrong) is not something we can abdicate to our rotting institutions. 

We must uphold it ourselves. There are no heroes here, only villains, villains with better publicity, and the victims they both leave.