This has nothing to do with him separating personal feelings. It's all about the fact that he is a slave to public opinion and he perceives MJ to be political kryptonite, the same reason he did not want to be photographed with supporters in traditional Muslim garb during the campaign. On a strategic level I get it, but it still makes me angry. I don't think it would have cost him much political capital just to affirmatively (the briefness doesn't bother me, but the fact that we may not have had any public comment at all if someone hadn't asked him does) and publicly recognize Michael's passing.
Dancemaster, first of all, no one said anything about voting based on MJ. Second of all, you have no right to decide how other people should prioritize their political beliefs. To you MJ may be just an entertainer, trivial in the scheme of things, but to an artist who feels the arts are not valued or treated seriously enough, it may be a huge slight. Obama's decision might signal practicality to you, but to a person who identifies with MJ in some way, it may feel like they themselves are being rejected on some level. Politics is about distributing the resources of society, yes, but it is also intertwined with social issues that are equally important to many people. You come across as condescending when you ignore this or decide that social issues are not important. They are important to many people and it is not for you to tell them they are wrong. Finally, if you think people are voting primarily on the issues now, then you are in denial. The attractiveness and charisma of the candidate, his (or her) public speaking ability, the gender and race of the candidate, the candidate's religion, the candidate's lifestyle and whether they are perceived as someone the public can relate to, the composition of the candidate's family, etc., are factors that have little direct bearing on the policy issues but still largely affect the way people decide to vote. The basis for voting is often emotional, not rational.