Interesting. I submitted my membership application a few days ago precisely because the Green Party finally took what i consider the correct and moral stand on this issue. In contrast, the other Parties voted in the House almost unanimously to condemn BDS activity. It brings the Greens closer to their roots as an anti-war Party and will help to overcome its reputation as being single interest (environment).
I don't think it is such a radical position. It is my feeling that a substantial minority (if not already a majority) of the public sees that the government of Israel is instransigent and something real needs to be done because mere statements deploring the illegal activity and disproprotionate violence in occupied Palestine are not working. The mainstream media, as usual, are magnifying the government/official position, lagging behind the public.
Should it have risked taking a stand at all, considering the other issues facing Canada? Yes, i believe this strengthens the foreign policy portfolio of the Party. It is consistent with a pro indigenous rights position. It is consistent with historical progressive movements' opposition to apartheid.