It's very simple. I disagree with the president and with the Democratic Party on quite a few issues. However, when it comes down to it, there is no question of which way I will vote on election day. This is because one party has become the party of fear and divisiveness, actively encouraging its members to highlight their "samenesses" and reviling the "others" (i.e. social and ethnic minorities). While there are certainly economic issues and issues regarding the reach of the federal government, those pale in contrast to the most basic human issue of all - do you truly respect me as a human being? As the offspring of an immigrant (legal)? As a transsexual? As an "intellectual elite"? As a non-Christian? Because if your core belief is that my being different from you makes it ok to legislate against me, to treat me differently, to castigate me, all without actually getting to know me, then I really really really really do not want you to be any part of my government.
So get out and vote, and vote for whichever candidate believes you to have human dignity. Mostly, that is the Democratic candidate, but I've read some news stories indicating that is not universal.