I've never actually seen West Side Story, but I've loved this song ever since a sociology professor played it for a 101 class I was taking. Mainly, I'm fond of the genuinely ambiguous stance it takes on "social ills" ca. 1957 and the failure of institutions -- legal, mental, social -- to either diagnose the root of a problem or constructively deal with it. These kids live their lives as full as they can, having been repeatedly failed by the system and marinated in pure vice from day one. What you're hearing is the ideological roots of punk rock.