The “plotters” original plan was based around Corbyn resigning. When he wouldn’t resign they tried to keep him off the ballot; they may still be desperately hoping they can succeed in that. If they really have to face Corbyn in a leadership election they know they will lose so why persist?
For some, simple, they have nothing to lose. They will drag the party into the gutter for the duration of the campaign and then they will either resign the whip or start proceedings to try and split the party.
In that fantasy scenario, not only will the “plotters” take a sizable number of Labour MPs with them, they will also take the party name, offices, and resources too. They imagine that if a few store managers were to leave Tesco they could take the Tesco name and the stores with them. I suspect that, beyond the fantasy world, the “plotters” also feel they have nothing to lose because they are aware that they will be deselected by their CLPs.
Others among the “plotters” may think that they are so important to the party that they will be courted to return to the shadow cabinet; another fantasy world.
Others yet imagine they will be permitted to stay as Labour MPs and proceed with a continuation of the campaign against the leadership; a continuation of the “sniping” and leadership challenges. Unclear why anyone would think any organization would permit that. If you are trying to take a family portrait and one member persists in exposing their junk, you take the photo without that person in it and you move on.
(Originally written 21/07/2016)