https://serhistorico.net/2018/09/15/los-moros-de-franco/(Left click for Google translate if not on mobile, on mobile your browser should offer it as an option automatically)
1st The Second Republic disappointed the hopes of change that Moroccan nationalists had placed in it. There was no notable improvement in infrastructure nor was autonomy allowed for the region. It is true that the Arabic publications of the Moroccan activists (and the activists themselves) circulated more freely in the Spanish Protectorate than in the French one, but this was not enough to seduce them to the republican cause.
2nd Most historians and specialists consider that misery, the pressing need to earn a living and, in many cases, to maintain a family was the main reason for enlisting in the rebellious troops.
3rd The rebel military demonstrated great ability to gain the support of the Moroccans. They prepared the recruitment in advance and their effective control of the territory (they held real power there to the detriment of the Madrid authorities) greatly facilitated their task. The role of figures like Beigbeder was key in this regard. They were also clever in presenting the Republicans as atheists who were enemies of religion and, therefore, of Islam.
4ª The Republic did not take advantage of the opportunity that was presented to it in September 1936 to turn around the situation in the Protectorate. We do not know if the attempt would have been successful, but it was not even attempted for fear of France's reaction.
5th France and, especially its military in the area, did not welcome the permissiveness that the Moroccan nationalists enjoyed on the Spanish side. This could explain, in part, perhaps, the recruitment of natives in their territory, all the more surprising given that at the time the Popular Front, an ally of Madrid, ruled in Paris.
The conclusions they draw. Interesting article.