Ok there's a bit here I disagree with.

1. I feel like one of the messages I got out of HP is that chosen family means more than given family. Such as when Harry gets sweater from Mrs Weasley and nothing from Dursleys

2. Just because slavery exists in the story, doesn't mean it's treated positively. There's an entire revolutionary movement for them in one of the books and Hermione is active in it. And Hermione is often a pretty safe moral compass.

3. No defense of the Goblins, this one is pretty bad.

4. Again, just because this idea exists doesn't mean it's supported. In fact, the bad guys are the ones always supporting it so it's pretty clearly a villainous idea.

Your arguments remind me of the illiterate folk who claim that Lolita supports pedophilia when the opposite is true. Just because something is present in a story doesn't mean it's presented as a good thing, or something worth supporting.

For the record, I do not support JKR and kind of wish HP would fade into obscurity, even if it was a defining moment of my childhood/generation.

What if the art has nothing to do with the artist's views?

For example, Burzum