You're referring to Civil Rights with capitals, and I'm referring to civil rights without. What I mean by this is that I'm not referring to the Civil Rights movement of the 60s, but a general upswing in attention paid to civil rights beginning in America sometime in the late 1800s.

For example, the Jim Crow laws were drafted sometime around when this song was presumably written (Skip James version is a cover, by the way) in the 1890s. James himself (born 1902) was raised right around the time the Jim Crow laws were starting to become increasingly controversial, culminating in the Voting Rights Act of 1965 (he died in 1969).

Coincidentally, women's rights were also brought to the fore in the same time period (as far as North America goes), with the first wave really taking off in the 1890s, around when the song was written. In 1920, the U.S. passed Amendment XIX, granting women (well, white women) the vote. This was a very fraught time for gender relations. Black women saw what white women had achieved, and began to invest in women's rights themselves, which the majority of the men of the time were absolutely not in favour of.

Cognizant of the political unrest or not (most people are affected by culture and environment without being explicitly aware of it), he was still a product of his time, and his environment surely played a role in shaping who he was, and subsequently the songs he chose to perform.

Again, I'm not claiming any of this is intentional on James' part, but it can definitely be analyzed from this perspective. Most music (and other media, such as literature, film, television, etc.) is much more representative of the culture and political clime in which it is written than artists are aware of at the time of writing it.