Well I only mentioned the Diaspora to relate to the idea that the Jews, as a people, were exiled from their lands and settled in foreign lands.
I'm arguing that them setting themselves apart *is* the reason why they were disliked. I would disagree that their monotheism would have caused the schism in and of itself because if polytheism was the norm then a people's god(s) would have little effect on attitudes since any other people's would have a different religion as well. In other words, "My Gods are better than your God" mentality would have prevailed. What would not have gone over so well is that the Jewish people tended to keep to themselves and maintain their customs. Any minority group living within, yet culturally apart, the confines of a majority "owned" state experiences similar attitudes of hostility (ie. Kurds, Gypsies, Muslims in India, etc.).
While I conceded that the Christian bias against Jews may have been a remnant of previous eras, I do not think this hatred is a relic of polytheistic days but rather due to the continuation of the Jewish tendency to remain culturally distant. It's interesting you bring up the more recent pogroms and exiling as I see this more of a consequence to Nationalism than the idea that the Jews killed Christ. Pogrom's weren't only for the Jews after all, German Russians where also persecuted around the same time. Pogroms were used against any minority group that the government distrusted. Jews would have been distrusted because although they lived in Russia they continued to maintain their Jewish customs thus setting themselves apart culturally. Nationalism brought about the notion of cultural unity of a collection of peoples throughout a region (nation). Jews and any other culturally different groups have a tendency to be treated poorly by nationalism in any form (well besides Zionism of course).