purpose of the second vignette?

What, in your mind, is the purpose of the second vignette ("White Trash Love Story") towards the greater meaning of the film?

In other words, the first and third vignettes clearly inform the climactic sequence of the framing narrative and therefore do not feel out of place. But the second does not seem relevant in any way that I could think of. Does it contribute anything in terms of theme, tone, motifs, or anything else? The only links I could find were generic, broad, and superficial, such as its general depictions of violence and the occult.