According to gangster-cinema logic, a gang boss wallows in crime and murder largely because he feels obligated (often willingly so) to look after the people on his turf: to keep the streets safe, his family well-fed and his business thriving. The contradiction is, of course, that by doing so a gang boss keeps the motor running on a machine that corrupts and destroys the very people he professes to protect.
In "American Gangster," that equation of irony is highlighted again and again: Harlem heroin kingpin Frank Lucas carefully builds himself a glittering empire of wealth and prestige, while just outside the diner where he habitually takes breakfast (Lucas prides himself on being part of the people), addicts are shooting up, killing each other over his product, and eventually OD-ing inside ghetto apartments.
In "The Godfather," mafia bosses had gotten together and agreed not to let drugs be sold on the streets or near children; the exception was Harlem since "they're animals anyway, so let them burn in hell." That line came out of typical 1950s racism. In "American Gangster," set 20 years later in early 1970, Lucas rails against such slurs, but he has no scruples about letting his people burn, whether on the streets or in hell, resolutely turning a blind eye to the consequences of his business. And come Thanksgiving, he throws frozen turkeys to the outstretched hands of the crowd that have gathered to bask in his generous good will.