African descent isn’t really saying much. Somalis (and other horn of Africans)are about as related to North Africans and Middle Easterners as they are are to sub-Saharan Africans.

I would say it because Somalia has an arabesque culture, is Muslim and whilst Arabic is not a day to day language in Somalia there are a decent chunk of the population who can speak it (like 10-30%).Also prior to colonialism and communism a greater percentage of the country could speak Arabic.

Somalia joined the Arab league cos it needed money and also cos Egypt wanted a foothold south of the Sahara (Somalia was invited to the Arab league by Egypt).

Arabs don’t know much about Somalia. They just know that Somalia is part of the Arab league and think it’s Sudan 2.0 or an African version of Yemen. Also generally the vast majority of Somalis in Arab countries (Yemen Egypt and the GCC countries) are able to speak Arabic.

Some Somalis claim to be Arabs because Somalia have a system of tribal lineages. When Somalis converted to Islam (1000 or so years ago) most Somali tribes seemed to have retconned their lineages to be connected to bani hashim.This kind of got diluted over time and so a lot of Somalis say they are descended from Arabs.

Somalis is a hybrid country. It is to Arabs and Africans what turkey is to Europe/ Middle East.

Some Somalis in the diaspora dislike associating Somalis with Arabs cos they see Arabs as being racist towards Somalis. I have no idea what Somalis in Somalia think about it.