Not sure if you realise, but Meghan used the photos of her with sick children to promote and advertise the outfit she was wearing. When she posted the photos, she included links where people could buy the clothes, so that she could earn commission on the sales. She used them to make money. Your claim that she didn’t use sick children is a lie because she so clearly did.
She did the same at a visit to the site of an antisemitic terror attack, where photos with the survivors were again used to advertise her outfit. She wore a shirt very similar to the Auschwitz uniform on that occasion, who knows whether that was through ignorance, or just a desire to make the biggest splash (and the most money) possible.
This is not remotely comparable to any other royal, or any normal celebrity doing a hospital visit.
As I said above, you don’t need to deny it or defend Meghan, she was evidently quite comfortable with trying to make money out of meeting sick children and survivors of a terror attack. That said, I don’t think she’s done it since, so perhaps she noticed the criticism and thought better of it, who knows.