Marxists view on religion is that the people turn to it as a result of their oppression. The solution to this is not the abandonment of the religion, but to fix the material conditions so that religion is not so necessary. 

An issue highlighted in Barravento is that religion cannot be relied upon to bring good fortune, as multiple fisherman die because of it. So the issue highlighted is that religion can protect, but also destroy and the villagers must learn to fend for themselves. In straying from the religion they become more independent. Simultaneously the independence of the villagers is deeply rooted in their religion, thus the conflict. 

The way the film is made seems very authentic and as though it has very little interference in the candomble and fishing elements. In this way the characters feel more real and the essence of the religion and people is better encapsulated. When the characters are given more direction, it serves to heighten the epic within the film and advance the plot. This is not to say natural actions and direction are not interspersed between the didactic and epic as it is truly a fusion. Ultimately this creates a very tenable feeling with the film, that I am not going to forget any time soon.