I can obviously agree that the interracial/gay parallel is unavoidable, and can serve as a useful tool to correct black support for a gay marriage ban. But I'm also pretty sure that Obama was raised in a single-parent household. Per wiki:
To the Editor:
Re “Gay Issues in View, Obama Is Pressed to Engage” (White House Memo, front page, May 7):It is deeply troubling that President Obama — whose parents could not wed in many states — supports the special exclusion of gay and lesbian couples from equal marriage rights. Surely his parents must have spoken of the difficulties of being treated as “less than” by society? How can he fail to see the parallel between that racial wrong and this one?
Obama's parents met in 1960... The couple married on February 2, 1961, and Barack was born later that year. His parents separated when he was two years old, and they divorced in 1964. Obama's father returned to Kenya and saw his son only once more before dying in an automobile accident in 1982.
So no, I don't think Obama was hearing many of these alleged conversations.