First, if you look at the minorities that the Left professes to love, they are all or almost all racial or sexual. Blacks, Hispanics, Women, the LGBT community. Their differences from the mainstream are largely physical, and what ideological differences they have are largely a result of the way that society has treated (or mistreated them). Jews are a true ideological minority. The Left can tolerate physical differences, but not ideological ones. See http://www.nytimes.com/2016/05/08/opinion/sunday/a-confession-of-liberal-intolerance.html?_r=0
The fact that Jews are a multiracial people defined by their beliefs conflicts with the Left's understanding of what a minority is.
Second, Judaism and Leftism are both religious/faith based ideologies. Not only is Judaism different than other minorities, but the nature of that difference means that it is ideologically in competition with the Left. The Left is naturally intolerant of other ideological identifications especially other religions. Jews dare to believe that their way, which is not the Left's way, is right. Jews are a both a nation and a religion and Leftism is hostile to both religion and nationalism. That isn't going to change.
Third, most minorities that the Left loves are oppressed or have been, and so can be convinced that they still are. The Left can rely on them for continued membership and support. The point is that the Left likes its minorities angry at the current order. That isn't the Jews anymore. As Western Civilization has become more tolerant and liberal, Jews have moved into the mainstream. As Jews have regained their country, they have become more a part of the world order. That same world order that the Left wants to overthrow.
As long as Jews were stateless and oppressed, they could fool themselves into thinking that they needed the Left, and the Left could look upon us as an ally. Those days are gone, and there's no going back. The Left can't use us anymore. So it's going in search of new disaffected allies such as the Muslim world. That is going to increasingly drive the Left to be anti-Israel and antisemitic.