A section in chapter two of A Queer History of the United States is called Slaves and Citizens. I had to read this section twice to get the gist of it. It deals with ideas and ''psychology'' rather than documented facts. So, let me try to explain how the author[Michael Bronski] relates slavery and citizens to LGBT oppression.
First I want to clarify that this not an attempt to compare African-American slavery to Gay oppression. What it does suggest is that slavery, and Native-American Oppression, set up a sort of psychological ''us'' and ''them,'' or ''natural'' and ''civilized'' mentality, or what the author calls ''othering.'' And that this othering was largely based on hypersexuality. This is hard for me to explain so bare with me. Anyhow, it basically is saying that the slaves and the indigenous peoples were sex fiends who had to be controlled, which played a part in the South's infamous concubinary system. Sensationalized narratives about white women being kidnapped and forced to live with, and sometimes marry, these ''hypersexual'' Native-Americans were extremely popular in Europe. They struck an unconscious cord with ''civilized'' society[s] in that civilization meant repressing they're own ''natural'' human desires and, in the end, exacerbating those desires. This is another example of how ''othering'' groups of people only hurts everybody in the end. So, the ''othering'' of non-white peoples created a social hierarchical heritage in the United States that extended to LGBT's.
This is subject is complicated and deep. I tried to explain it in my own words. I think I explained it correctly but it deserves further study.