A word that makes a black person sound smart when they're talking about a group of white people that owned slaves (such as the British, in particular slave owning British families and not all British families), but makes a black person sound ignorant and retarded when talking about a group of white people that never would have owned slaves hundreds of years ago.
Ike thought he was a badass, so he called the Polish guy, the Albanian guy, and the Russian guy a cracka because he called every white person a cracker, based on principle. He must've thought he knew everything about every group (or assumed everybody but him was an innocent bystander in life) without even knowing these folks.