Often, co-op meetings are sparsely attended and as a result the anti-Israel crowd can take over and force their opinions on the entire group. Only people who are members of the co-op can attend and vote at the meeting, and the anti-BDS organizers are trying to get as many members to come as possible to ensure that the measure is defeated.
If you are a member of the co-op, or if you know someone who is, please encourage them to attend (and to RSVP to the pro-Israel organizers.)
More information here and here.