I think there's a some truth in what you say about Dumbledore, but there's more to him than that. Dumbledore is certainly one of the things Harry and Snape have to overcome!

I prefer not to refer to things Rowling said in interview because they are not actually part of the story, and because they have to be seen in the context of the whole interview and the specific question, as well as in relation to other things she said in other interviews. And to the books, of course. I can have no idea of the scope of the comment about goblins that you mention, whether it's about that particular claim by goblins or - as you are suggesting - about the validity of the goblins' world-view, and what wizards' attitudes to them should be in general!