I think that Republicans were much more positive about Obama when he won the first election than you’re giving them credit for. If we assume that 35 percent of the voting population are Republicans and Obama’s initial disapproval rate was 12 percent, then Obama came into office with a good percentage of Republicans approving of him.
After Obama was in office and Republicans increasingly disapproved of him, that’s a result of his actions in office, not an inherent dislike of him.
Even though I think that Obama was often incompetent in the role of president, I approve of him as a person. I wonder how the people conducting the polls calculated the ratings.