The obvious question is why Stalin, despite his anti-Semitic nature and statements, agreed  to the creation of Israel? What did he hope to gain, and why shortly thereafter did he turn against Israel?
He had two clear hopes. He hoped that the creation of Israel would create chaos in the region and bring about the downfall of the British Empire. Then he hoped that Israel, with strong socialist leadership, might become a quasi-satellite of the Soviet Union. When neither of these self-serving objectives were realized, a few months later Stalin was railing against Zionism as an outpost of American imperialism.