Wrong. Kasper was appointed by the pope to one of the highest and the single most visible position in the Vatican. He serves at the pleasure of the pope, and he speaks on behalf of the pope. If the pope doesn't believe as Kasper does that the Jews have their own salvific covenant, then he should speak out and say so, and he should have long ago dismissed Kasper.
And let's also point out that Kasper's predecessor wasn't any better. Kasper is merely carrying out the will of the pope which has been reflected in many appointments, actions and statements.