Why is Sabeel calling for "morally responsible divestment" from Israel?

The campaign of disinvestment in Israel is modeled after the campaign of disinvestment in South Africa that helped end apartheid in 1990. Like that campaign it does not seek to address the problems of any and every nation in the world, which could only diffuse the issue and destroy its effectiveness, but focuses on one nation and one situation seen as particularly egregious.  It does not call for general disinvestment in Israel, but rather for a selective disinvestment in those companies that are making money on the Occupation in hopes of putting some pressure on these companies to withdraw from their support of the Occupation and to raise consciousness about the Occupation in general.