How does it relate to racism? Sure, there are nutjobs who spout all sorts of things about all sorts of people in various places on the internet. I mean, when Catherine had stomach surgery, which it later transpired also became a cancer diagnosis, even though there had been an announcement that she would take some months out for health reasons, instead of respecting her private health issues, the response and bizarre conspiracy theories not just from nutters online but even supposedly respectable media was insane. Some thought William had done away with her or that he was having an affair and that's why she had disappeared - even Stephen Colbert repeated that garbage on his show. The media - even outlets that should know better, such as Reuters or Getty pictures or Instagram - had a frenzy over her slightly edited Mothering Sunday pic (as though every other photo posted on social media isn't edited), with suggestions by supposedly serious media that the whole pic had been doctored to make it seem as though she still existed, the implication in some quarters being that something had happened to her, some even implying that William had offed her.
There was all sorts of crazy stuff put out by the Sussex Squad, such as William had killed Thomas Kingston, Lady Gabriella Windsor's late husband. There were even doctored images of William supposedly sporting a black eye that the Sussex Squad were circulating as evidence that he had been in a fight with Kingston!
As for Harry and Meghan's kids, some people have said they don't exist and things like that. Of course, that is absolute nonsense, but they have been so weird about hiding their kids that it allowed conspiracy nonsense to fester. More to the point, that kind of stuff doesn't fly here. If you want to argue with people who say those kinds of things, go to the places where they gather.