I don’t have a firm position on either side yet, but I do think there are very real questions to be asked of this case and of the trial.
That said, there’s a version of this which doesn’t involve an active cover up. I think it’s possible that a doctor in a hospital that is coming under scrutiny, especially a doctor with a TV career, might see that one nurse is on shift for many of these incidents. Could she be causing the deaths? Is it not in fact our incompetence? That doctor might want this to be what’s happening, because it takes the heat off him/his fellow doctors/the hospital.
Once that accusation is made it snowballs. It’s a big dramatic emotive story and it offers comfort to many who otherwise feel that their jobs or reputations are at stake. On an individual level, if everyone else is saying it, then it might well be true.
Once you involve the police, whose job it is to find a culprit for a crime, not to say that no crime occurred, it takes on a life of its own. Once it gathers speed it becomes impossible to voice doubts because, as seen in a small way in this very thread, you’ll be smeared as a “baby killer fan”.
I think the way that this evolved could be complex and subtle and insidious. I think that version is perfectly plausible. If Letby has been wrongly convicted it doesn’t require a ‘gang of four’ in capes conspiring in dark corners to put an innocent woman away. All it needs is a misunderstanding of statistics and an emotional/financial/personal investment in her being guilty. You can believe absolutely anything if it’ll benefit you to do so.