I don't know who started the Kenya stupidity. He never said that his birth certificate is private. Everyone running for president has to have his/her citizenship verified. It probably started because his father was born in Kenya and yes, I think that there is some racism involved. There was a reporter who called Obama's grandmother, or step grandmother, in Kenya to ask where her grandson was born, meaning Obama. The interrupter said son instead of grandson, and she answered Kenya. (I heard the tape,but it was pretty poor quality.) I would not be surprised if it were the Hillary camp who started some of this nonsense. The birthers would not have gotten far with this if Obama's parents had still been alive.
Romney doesn't have Mexican relatives.. His grandfather fled to Mexico because he had more than one wife. They were American citizens and never gave that up.