I find it strange that people look back on it as embarrassing or when the UK lots its collective mind.
Diana was the most famous woman in the world before the internet and 24 hour news became fully functional. She had arrived in the RF as a gauche nineteen year old and everyone had followed her progress and her blossoming in a way, in to someone who went from completely powerless to someone who grew in to their own skin.
The other attraction was that she was very very flawed, and admitted to it.
And of course she had a natural gift for charity work, some of which, like AIDs, homelessness and land mines, were quite controversial at the time.
And being as young and tall as she was, she was a great clothes horse.
And she was engaged in this David v Goliath struggle with her in-laws.
All of this meant that she had great universal appeal.
Also, the UK is pretty buttoned up about death and dying. We don’t talk about it. We are expected to be strong in the face of loss and carry on as usual. Hence the common occurrence of British men breaking down at the death of their dogs when they barely cried at their mother’s funeral.
Diana’s death was a similar scenario I think, because she was so famous, her death gave people “permission” to express grief collectively, that had previously gone unacknowledged.
And whether you loved or loathed her, most people could see that what had been done to Diana was fundamentally unfair, that her life had been pretty tumultuous, and they simply acknowledged the sadness of an energetic, attractive, mother of two in her mid-thirties losing their life in such an abrupt way far too young.