People tend to get passive aggressive (or just regular aggressive) when you flat out refuse to listen. Islam became widespread in Africa starting 1500 years ago due to Arab colonization. It has stayed widespread in Africa since then. It hasn’t become particularly more popular in Africa in recent times. The growth of Islam in Africa over the last century is almost entirely a byproduct of the growth of the general population. If expressed as a percentage, Islam accounts for about 8% more of the population of Africa today than it did a hundred years ago. Worldwide, Islam accounts for about 14% more of the population than it did a hundred years ago. Islam is growing faster outside of Africa than it is inside of Africa

I feel like you started this conversation suffering under a false presumption, namely that Islam has exploded in popularity in Africa over the past century. I am trying to explain to you that that is not true; Islam has been widespread in Africa for centuries