Out of responsibility to the united [right wing]bloc, it is important that the votes of the students of Rav Mazuz will go to Shas, being very close to the minimum threshold.

  -- Spokesperson for Habayit Hayehudi, informing Eli Yishai that his merging into their party is now off the table

That's a very nice sentiment, but since Eli Yishai is not backing down, as of now, and will be running as an independent party, the votes of Rav Mazuz's students will [mostly] not go o Shas but will go to Yachad and will most likely be wasted. Thus, by not bringing Eli Yishai in, they are not helping Shas and they are allowing Yachad's votes to be wasted. They are not obligated to help Eli Yishai or Shas, but there is clearly no truth to what they are saying...