Could be, but so what? I couldn’t hold that against him. There are an unlimted number of things I can hold against him, but not that.
Back when he was growing up it did matter. I believe his mother and grandparents told him they were married to cover. Later he found out they were not. I think that is the whole theme in Dreams of My Father. He tells of finding his birth certificate in the closet or drawer, I think he discovered they were not married, so he began to question who he was and also who Barack Sr. really was. Dreams is the story he concocted based on the lies he was told and the story he wanted to be true.
Once one tells a lie, one has to keep on telling lies. I think that is where he finds himself.