1. It is so unfair to the English people and especially the Royal Family to apply the R-word to this situation.
2. The Duke simply made a terrible mistake in marrying the young lady, who is a very spoiled and self-centered person.
3. Well, of course, people were somewhat astonished that he was marrying a person of her background. As far as I know, in recent English history at least, everyone in English royalty has been Caucasian. It is only human that some people were startled by this sudden change. (By the way, I have read that the Duke has a reputation of doing things to infuriate the Royal Family.)
4. The Royal Family, I have read, has gone out of its way to welcome the Duchess and to make it clear that Her Majesty has no problem with the Duchess's background. It is the Duke and the Duchess that have implied that there is a problem where there isn't one.
5. I agree with some people that Her Majesty should strip both of them of their titles, if they are so miserable. Without those titles, they will discover that very few people either in England or Canada or here in the States have any interest in them.