Why is Al Qaeda interested in the Sahel?
Why would you think they wouldn’t be?
Jihadists want to bring the entire world under the dominion of Islam, and they don’t have any particular national, ethnic, or sectarian origin — they come from all over, and get funding, weapons, and other support from all over. Africa’s being taken over by groups sponsored by Iran; Iran’s been far more successful at jihad than any other terrorist state, and is nearly at the point of being more successful than all others combined. They don’t make any apology about what they’re about, and don’t have a fragmented ruling class (or at least, none with any power to speak of).
The separatist movements in Africa (particularly in the Horn of Africa), in Pakistan and elsewhere in Asia (including the Philippines), and even in Europe (at least two in the former Yugoslavia, for instance) have as an overall goal the creation of another thirty or forty “countries” in order to take over the UN General Assembly. Instead of waiting around for them to do that and grousing about ‘US out of the UN’, it makes much more sense to make sure they don’t succeed, and to do whatever it takes to make sure.
The Iranian public is ruled by a mullahcracy, which runs a police state, and employs foreign thugs (from “Palestine” for example) along with local fanatics. It’s lucky that an entire generation of fanatics wound up fed to the guns during the 8 year Iran-Iraq war, or the prospects and problem would be much worse. As it is, the oil shipping routes in the Red Sea as well as the Persian Gulf are under Iranian offensive missile umbrellas, and Iran has been working for years to subvert Latin America.