Stalin was hardly an anti-Semite. He did have some rude things to say about “regressive” religious-Jew culture, but he wasn’t generally against the Jewish people or identity.
His anti-Jewish paranoia grew after the War. See: http://yalepress.yale.edu/yupbooks/book.asp?isbn=9780300104523
That’s Stalin for ya . . . He had led his country to victory in the Great Patriotic War, he was more secure in his position than he ever had been, and he was still looking around for plots and threats.