Yeah, this is key. As chief prosecutor he had to act on whether there was sufficient evidence for prosecution, to justify a case being brought at the taxpayer’s expense. It wasn’t a reflection of whether Keir thought Saville (or whoever) was guilty - the fact we now all know for def he was, and there’s now plenty of evidence to that effect, doesn’t change that.
No surprise that that nuance (or, you know “accuracy”) will be lost when the slur is spread by the right wing press and shithouse Tories,