Arabs are notorious for slave trading. And they treated their Negro slaves far worse than their white slaves. Not to mention the general castration of black slaves. (And yes. Racism (if real) is a Bad Thing.) I am unaware of the hatred going both ways.
By the way, “Lo tignov” in the famous midrash (Yalkut Shimoni Shemos 20;286) means kidnapping, not stealing (see Rashi on Aseres Hadibros), as opposed to “Lo tignovu“.
… נגלה על בני ישמעאל אמר להם מקבלין אתם עליכם התורה אמרו לו מה כתיב בה אמר להם לא תגנוב אמרו לו זו ברכה שנתן לנו אבינו שנאמר והוא יהיה פרא אדם וכתיב כי גונב גונבתי…
Anyway, to illustrate anti-Black racism among Arabs, consider, if you will, the humble chocolate-coated marshmallow treat. In Israel, one variation is called a “Krembo” (Translation: contains cream). Other countries had names related to “Negro”, but not necessarily derogatory (especially back then), as far as I can tell.
But the Arabs go and call it Ras Al-Abed, or “Slave head”!
To soften the insult, perhaps, it has been since renamed (among other things) “Sambo” (of course, Wikipedia fails to mention “Sambo” is also a racial slur!).
P.S., That’s what is so unique about Jew-hatred. Only the hated Jews could bring about such inspiring achdus even between Blacks and Arabs!