The poison in this Warrel Dane song is blind following of religion(s). "Color me unuseful/when you color me away" is basically saying he's useless when beholden to some organized way of thinking, in this case religion. Everyone repeats the words, empty and shallow. Totally trained to think according to another's point of view, stifling your own individuality in the process. "All our love has become emptiness..." for me, it means the person has lost all sense of him or herself in such blind obedience. "Everybody stand in line and take the poison...the poison tastes divine.." is self-explanatory. Take what we tell you and question nothing; take it fast, much like bad medicine, so you don't actually get to think of how genuinely bad it is for you. Warrel Dane is a magician and poet with the best of therm, hands down!