So the quantum physicists tell us.
I was very interested to see The Sun front page leading off on the bullying of SC by the 'Sussex Squad', as it was, afaik the first time that the existence of the Squad as an organised/semi-organised operation has been acknowledged by the legacy media.
I didn't use to believe in the existence of the Squad as a coordinated body, partly because I have some professional knowledge of social media standoms and understand that although they look coordinated from the outside, it's mostly superfans with personality disorders in online Discords with a self-appointed queen bee whose talking points they parrot. They have loads of accounts so there are often far fewer 'true obsessives' than it may appear from the outside.
After the bullying of Kate I spoke to someone in the industry who had more of a front seat to the Sussex Squad antics and now I do believe they are semi-coordinated - enough to be able to fan out across sites with agreed talking points which are adapted to the style of the site, and enough to buy up Meghan's products quickly.
I don't believe H&M are the 'organising' mind behind the Squad and I don't think either of them disseminate the talking points. I think they are probably aware of the key individuals but have no control over what they do.
It's difficult to try to change your superstans' online behaviour because in order to do so, you have to acknowledge that the behaviour is happening in the first place. Beyonce and a couple of K-pop stars have spoken out in the past and urged their fans to behave better - and all credit to them for doing so.
The people who join these standoms tend to be unemployed or have unstable employment and a fantasy parasocial relationship with the celebrity in question. They tend to overly identify with the celeb and see it as their role to 'protect' the celeb; they are very proud of their role in the standom and it's often a major part of their self-image.
It can get dangerous when standom activity bleeds into the real world. I've posted before about the toxic standom of Nicki Minaj - they harrassed and doxxed a woman who was the victim of a paedophilic rape by Minaj's husband, years prior (he had pled guilty and as a result is a lifelong registered sex offender, but the stans nevertheless believed the victim had lied) and they vandalised the grave of the mother of Megan Thee Stallion, a talented rapper whom Minaj strongly dislikes. Megan had lost her mother to a brain tumour, suddenly and at a young age.
I'm aware of a YouTuber who claims to have evidence that members of the Sussex Squad has stalked her IRL; and I think there's another who claimed that her property had been vandalised, though I don't know the veracity/details.