The "black Israelites" are just another manifestation of black jelously and hatred of the Jews.
They are vicious anti-semites.
In general, Black Hebrews do not claim that the original Israelites were black. Their theory is that some Jews were exiled to Africa after the Destruction of the Temple ( Remember that Africa and Sinai were comunicated by the Suez isthmus). According to them, some Jews came to Africa and mixed with native blacks. They were later taken as slaves to America, and now want to live in Israel ( since according to their theory) they have Jewish ancestors. They live in Dimona and are a small minority, faithfull to the land and the State, even though they had to struggle for decades to be allowed to stay. I sincerely do not see any reason to hate them.
Their religion is quite strange, they celebrate Pesach ( the week without leaven), but have also added other customs.... the sugarless week ( in which they do not consume sugar), the week without cooking (in which the only eat raw vegetables).
etc. They also avoid to put fruits and vegetables in the same dish or bowl (perhaps because the Torah forbids to grow vgetables in the vine.......)
The base of their ideas seem to be too weak to be considered Jewish, but if they are faithfull and honest, what's the problem? There are many peacefull Goyshe minorities in Israel. Even the Torah provides the concept of a Guer Toshav ( a Goy who is allowed to live in Israel as far as he does not violate the Noahide Laws). Then.... what's the problem with them?
? Just their black skin?
?!