Yup, when authors go on the road to push their books, they give radio talkers and tv takers and late night takers a thumbnail sketch of their life.
For years and years 0bazo never corrected the record
You are right. There are 2 possibilities here.
His supporters have suggested that he really was born in Hawaii, but by giving his birthplace/background as Kenya, it made him more exotic and interesting to his readers. (Pretty far-fetched, I think)
The second point is most non-supporters believe he attended college as a foreign aid student. So, if he was born in Hawaii, he cheated the colleges for the foreign aid grants BUT if he was born in Kenya, he cheated his way into the presidency. In addition to manipulating and altering his birth certificate, he has never let anyone see college records that would confirm his foreign student status.