I'm not sure this is because Obama looks at it as not playing the race card and taking the high road. I think at this point too much press about such incidents would hurt his appeal to democratic delegates by painting him as perhaps unelectable due to race, where Hillary's sex might not cause nearly such response. With much of the media apparently in a pro-Obama state I think they realize this and thus are keeping it to a minimum at this point. Granted, those who would vote against either for such reasons are for the most part probably firmly in McCain's camp already, but I'm sure it's been cast off as bad press in any case.