Sad to hear that being successful in work impacted negatively in their private life this way.

There are anti foreigner sentiments in every country, for Japan the right wing Sanseitou party made the news by winning a few seats running on “Japan First” in the last election.

I have not checked out the SNS comments, but I think they are separate issues: the insensitive comments were probably about the husband’s race or nationality, not about his royalty status. There was also the privacy problem of some people posting photo of the husband, who is not a public figure, online.