He blames the Jews for the death of his father, who died in World War II.
Israel consists of Israeli Arabs, their largest minority, thus by extension, he hates them as well.
Just semantics, in any case. Roger Waters hates Israel and Jews. An Anti-Semite is a hater of Jews.
Arabs are half-Semitic and half-Hamitic if the assertion that they are descended from Ishmael is true, whose mother was Hagar, an Egyptian.
Those who used the term “antisemite” to describe themselves explicitly used it in the context of their hatred of Jews only.