The Moral High Ground

In one of the most prominent debates, just 2 days before the late, much-to-be-regretted EU Referendum, the Mayor of London accused people who want to restrict immigration to the UK of hate. This strong word is effective in claiming the high moral ground for the speaker.
London's Covent Garden used to have this graffito: "Hell hath no fury like a vested interest masquerading as a moral principle."
The Mayor of London is Labour and most immigrants vote Labour.
Immigration causes ill feeling. That is what the Referendum was mostly about.
Provoking ill feeling is morally wrong.