What constitutes a celebrity? A decision was made to limit the list to entertainers, and to exclude antisemitic politicians and writers who surely deserve their own lists. All in good time. (Which is not a threat. If people go on record with their views, the public is allowed to take note.)
How is such a list useful? First and foremost, it serves to tell the world that antisemitism is evil. If we see it, we will call you out on it. Because antisemitism is evil and this is society's way of enforcing morality.
What is antisemitism? The official IHRA working definition of antisemitism aside, sometimes it's difficult to know, in particular when antisemitism involves criticism of Israel. Each name in the list is linked to an online news piece that serves as a source for the allegation (more about methodology HERE). Readers may not agree with every inclusion. For purposes of this list, the working guide was "where there's smoke, there's fire."
Feel free to email me to suggest other candidates and if a source can be found backing assertions of antisemitism, the list will be updated to include them.