Modern civilization is centered around animal-killing. Karmis are advertising that without eating meat, their vitamin value or vitality will be reduced; so to keep oneself fit to work hard, one must eat meat, and to digest meat, one must drink liquor, and to keep the balance of drinking wine and eating meat, one must have sufficient sexual intercourse to keep fit to work very hard like an ass.

From Srila Prabhupada’s purport to SB 4.27.11