I'm not at all educated on this particular subject, but it seems to me like a logical extension of his rhetoric. Communism is an evil jewish plot to rule the world or whatever, and also eastern europeans are low-iq uncivilized mongrels or whatever, so the Soviets have gotta go. They're evil. We've gotta be the good guys and go stop the bad guys. It's harder to convince everyone that you're really the good guy if you won't go fight the ones you've made quite clear are the bad guys.