The discriminatory document Apartheid Week participants must agree to is entitled the "Basis of Unity for Israeli Apartheid Week International Coordination." That agreement calls on people to oppose Jewish and Israeli nationalism, or Zionism, because they claim "it inherently discriminates against those who are not Jewish." (There isn't the slightest indication of concern about Irish nationalism inherently discriminating against those who are not Irish, Greek nationalism discriminating against non-Greeks, Finish nationalism privileging Finns, Saudi nationalism discriminating against non-Saudis and so on.)
Meanwhile, in dramatic contrast with Apartheid Week's hostility toward self-determination for the Jewish people, the Basis of Unity explicitly supports calls for "the Palestinian people's inalienable right to self-determination."
It should be noted that there are many well-intentioned people, including in Israel, who support Palestinian self-determination. It's when this support is coupled with the denial of an equal right for the long-persecuted Jewish people that the ideology becomes one of rejectionism and discrimination.