I don't know what the definition of "accountability" is in climate research, but a threefold error is terrible science, it should have been caught in peer review, and everyone involved owes the scientific world an apology.
"We're still right, it's a terrible problem," only shows clear bias towards demonstrating there is a terrible problem, and that's how they missed this. All of them, peer review, everything. It's a massive methodology screw up that can easily be accounted for in STATA or whatever they're using. It is a solved problem to identify statistical outliers and compensate for or eliminate them.
What's "terrible" is this is more fodder for climate deniers and people with general scientific trust issues.
The only appropriate answer is, "We all made an egregious mistake." Don't tell us you're right, because that tells us that you went into statistical analysis with a foregone conclusion. Even if it's the correct conclusion, and it is, it reflects badly on the entire scientific community if you fuck up the evidence. Worse, some will assume you fucked with the evidence.
Mea culpa and STFU. Let the adults cover your butts and your reputations.