Here's why:
* Berbers: The majority of the invading force were Berbers, who were already heavily influenced by Arab culture and religion.
* Arabs: The invasion was orchestrated and led by the Aghlabid dynasty, which was an Arab dynasty ruling in North Africa. Arab soldiers and administrators were also involved.
* "Moor" as a term: "Moor" was a term used in medieval Europe to refer to Muslims from North Africa, regardless of their ethnic origin. It was not always a precise term, and often referred to any Muslim from the Iberian peninsula or North Africa.
Therefore, while the Berbers formed the majority of the invading force, it's inaccurate to say they were exclusively "Moors". The term "Moor" is more of a broad cultural and religious designation rather than a specific ethnic group.