Notice that the theme of the event was supposed to be "United Against Racism."
Which is funny, because the intended speaker has written about racism - Arab racism against black Palestinians.
On his Facebook page, in Arabic, he wrote last month:
About three years ago, I read an article in the Al Monitor newspaper titled "Black Palestinians Shrug Off Racism"… After I read the article, I was angered, thinking "What?! We don't have racism in Gaza!" So I decided to write an article that would refute the original article. Then I began to conduct interviews with some dark-skinned youth, and I was shocked to find that yes, indeed, we do have despicable racism in Gaza, and dark-skinned people suffer because of our racism.The Al Monitor article mentions "According to Gaza Through History, a book by Ibrahim Sakik, wealthy families in the Gaza Strip participated in the slave trade hundreds of years ago." But there is not a single book about the history of black Palestinians.
After I published the article, I was surprised to see that it reached the (Ministry of) Interior, and the criticism began to pour down on me, as well as accusation of being a traitor, and (people said that) I am trying to distort Gaza's image… And no one thought or felt even once what the wronged people (i.e. the black Palestinians) feel because of our racism.
(h/t Ibn Boutros)