Regardless of what a few people may say about racism, I believe that the vast majority of folks are dissatisfied with Obama for Obamacare, broken promises (especially Obamacare), and an apparent lack of negotiation skills with Republicans.
Savvy politicians know that, to get things done in Washington, you must bargain... be prepared to give up a little in order to gain a little. Obama doesn't have this talent and it is why he will be remembered as an unproductive president.
With Obama, to paraphrase an old Rudyard Kipling saying, it's...
Oh, Democrats are Democrats,
and Republicans are Republicans,
And never the twain shall meet.