Religious Dispatches had an article about the Cult of Santa Muerte (Saint Death) in Mexico. Most attribute it to the drug cartels and violence pertaining to gang rivalries and such. I think the explanation is deeper and is embedded in Mexican history and the interplay between indigenous peoples and the the Spanish Church. The Catholic Church is primarily responsible for this nonsense in that its hold on the common people of Mexico since the phony apparition of the Virgin of Guadalupe in 1531 has been iron-fisted. (Has anyone noticed that most "miracles" are denounced as fraudulent by the Church except in such instances as the Vatican can find a use for them?)
If extraordinary claims require extraordinary evidence, it may be said that where a religion has such enormous influence, the Enemy (always a bugaboo designed to reinforce the fear of death) must be all the more dreadful. A nation only gets the kind of Devil it deserves. Death is what the Church is really selling. Note that all the monotheisms are dualistic, itself a kind of contradiction in terms. If the Good God is winning at the moment, I'll side with the Bad One. I will also check myself into an institution for the mentally handicapped.
Meanwhile, there might be speculation that as the cartels take over more and more territory and the blood is spilled voluminously, the cult takes its sustenance from the gloom and doom. There is even the possibility that Santa Muerte is a kind of antinomian Gnostic faith exalting bloodshed as a kind of reverse baptism, or else, perhaps, they believe much as do present-day (and presently persecuted) Iraqi Yezidis. These folks actually believe that it is the Devil who has and always will rule the world, and it is for this reason that they worship Satan. One thinks of certain sects in the south of France who believed the Judeo-Christian "God" to be the Devil. Thus, to the Cainites, all Biblical "villains" (Cain, Korah, &c.) were actually heroes, while such devout Jewish "heroes" as Mosheh, Yeshua, &c.) were excoriated as evil. You can imagine what they thought of Judas of Kerioth.
Given what we see around us daily, I might be inclined to agree with them were I not convinced all such thinking is a complete load of cobbers.