and then I realised that their actual evidence amounted to: "she still kept a scrapbook of cuttings in her 80s and had the temerity to answer fan letters"

To which the logical response is that someone who gets fan letters must have had genuine appeal (particularly if she was still getting said fan letters in her 80s — I can’t tell if that’s what you’re saying), or no one would have bothered writing them. So it was a hatchet job on her AND on her fans, I guess.