1:The metaphorical drink that gives haters their ability to hate, just like Gatorade give athletes the fluids to compete physically. Combined by mixing the words "hater" and "gatorade". Hatorade is metaphorically the color "green" with envy.
2: the act of hating. sometimes called "drinking hateorade"
"Hey asshole! Stop drinking that hateorade and get your own bitch, you hating bastard!"