Carter Ruck were trying to suppress anyone knowing about the report, to such an extent that they tried to stop the Guardian reporting on a parliamentary question that spoke about it. Twitter, fueled from the outrage in regard to gagging the Guardian, started to link to that report extensively.
The longer Carter Ruck decided to persue this course of action, the more Twitter would link to the report. Therefore, it was wise for Carter Ruck to remove Twitter's fuel. It was wise to stop attempting to gag the Guardian. (Attempting to sue all those on Twitter would be unfeasible, and suing Twitter itself would add even more fuel to the fire)
I have no proof this is what Carter Ruck thought. But it's certainly a logical and sensible course of action for Carter Ruck, which makes it likely.