That the dissatisfaction reached a crescendo the week before the party's conference was precisely because it was the week before the conference, when anyone who cared was more likely to be thinking about Labour's fortunes and the impact of its weak leadership.
If the criticism seemed harsh and overly impatient, it has to be seen in the context of the past four years.
The party had been conspicuously united behind Phil Goff despite widely held reservations almost from the moment he assumed the leadership.
Much good that show of unity did them.
Now they were being asked to extend that faith to a political neophyte who, if anything, had fewer weapons in his arsenal.
If politics is a contest of ideas, it needs well-armed champions. If there was a coup attempt brewing, right then, it was the most publicly signalled coup in the history of coups; the stirrers may as well have posted it on Facebook.
With the media on high alert to detect the merest hint of insurrection, the stage was set for high drama.
Cunliffe, under intense scrutiny, did not help himself. He rather likes attention, which usually isn't fatal in politics. But it wouldn't have taken much to damn him. He was seen to grin too brightly; hitch his eyebrows too high; and preen too blatantly in front of the cameras (imagine a politician caring about how he might look). He mimed his disloyalty, according to the Listener's Jane Clifton.
Asked repeatedly by TV3's Patrick Gower whether he'd have a go at the leadership, Cunliffe replied, "That's not a matter for this conference ... It's not a matter for this conference ... It's not a matter for this conference ... It's not about this ...", and so on, which was clearly not the correct answer.
When Goff stepped down last year, the contenders embarked on a presidential-style roadshow in which the Labour membership was given a chance to size up the leadership prospects. The rank and file is said to have favoured Cunliffe but Shearer narrowly won the caucus vote, led by the old guard, who, it's now well known, deeply dislike Cunliffe (though why is not clear, even in a town not known for keeping secrets. One Labour MP who asked what Cunliffe had done to deserve such antipathy is still none the wiser).
Cunliffe, rightly praised as one of the Clark Government's most effective and fearless ministers (he unbundled Telecom's local loop monopoly, succeeding where many before had failed), might be forgiven for feeling hard done by.
But the reality is that whatever Cunliffe's credentials, his thwarted leadership ambitions would have been dead if Shearer had lived up to expectations. No one would have been hankering after Cunliffe's superior grasp of finance or communication skills. Or wondering why Shearer didn't follow the canny lead of Helen Clark and John Key and keep his talented rival close, giving him the deputy leadership and finance portfolio.
I asked an activist who'd agreed with my earlier assessment of Shearer whether the conference had changed her mind. Yes, she replied. "He is a man with a mind and a heart, and learning the 'political arts' fast."
Did Shearer's much-praised speech silence the doubters? Was it the speech to bind all of Labour?
Those at the conference were certainly excited. I watched it on YouTube and was less smitten. Maybe you had to be there to feel the rapture.
However good, it was asking a lot of one speech. Especially when Shearer's subsequent TV appearances show him bumbling his way through straightforward questions on Labour's new housing policy and Cunliffe's summary execution.
It's nonsense to say this doesn't matter.
There is no "rightful leader" of the Labour Party. The position isn't Shearer's by right, nor Cunliffe's for that matter. It ought to be threatened if enough people feel the incumbent hasn't earned it.
