I'm white & supported Obama twice & still do, but his administration has made several big mistakes, I think. Maybe they were inevitable given the GOP forces against him and the corporate domination of US politics today. But I think they hurt him with white voters a lot.
1. Although his bank bailout and economic stimulus package rescued the US economy in 2009, saving us from a potential Great Depression, the bailout especially benefited Wall Street -- not the average homeowner.
The economic stimulus package was urgently needed -- but it was too small, and it failed to bring down unemployment fast enough, and it didn't keep the average US wage from stagnating, while the richest 1 percent continued to get richer.
Many white voters who supported Obama in hopes that he would fix the economy -- and fix it for THEM -- are understandably disappointed about that.
2. Obamacare - the Affordable Care Act -- is a huge step forward towards helping the uninsured in the US, but it's extremely complicated, it seems to violate civil liberties by forcing Americans to buy individual insurance policies from private companies, and the people administering it bungled the computer program for signing up. Also, Obama really did tell some foolish whoppers in selling it to the public - like "if you like your health insurance, you'll be able to keep it." No one could have guaranteed that.
So I think many white voters, and some nonwhites, too, feel burned by Obamacare. Plus, of course, the GOP has been telling scurrilous lies about it from the beginning, which doesn't help.
3. In 2008, many white union members voted for Obama in the hopes that he and other Democrats would push through the Employee Free Choice Act, EFCA, to make it much easier to organize unions in the face of corporate hostility. Then the Democrats in the Senate failed to support EFCA enough to pass it, and Obama's White House let it die. I'd guess that many white union members feel burned by that.
4. Racial fears & racial anxieties & fears that Obama is a "secret Muslim terrorist," of course, have played a role from the beginning in why SOME white people don't like Obama.
5. Like almost every recent president, Republican & Democrat, Obama stupidly or dishonestly campaigned for the White House on the grounds that he would "bring people together again," although actually the words were what Richard Nixon spoke in 1968. Like almost every other recent president, Obama failed to bring the country together again -- failed to get Republicans & Democrats working nicely with each other in Washington -- because the Republican Party and the Democratic Party have opposing interests.
Anyone who was foolishly hopeful that Obama would succeed in uniting the country -- after Bush, Clinton, Bush I, Reagan, Carter, Nixon, Johnson & Kennedy had all failed -- must be disappointed that Washington DC is just as bitterly partisan as ever.
On war & peace & foreign policy, many white voters also seem disappointed with Obama because he hasn't been tough enough or decisive enough with ISIS, Iran, Putin, etc. However, I think Obama basically gave the American voters what we wanted in 2008 in the way of a less warlike & aggressive foreign policy, unless of course you count drone warfare. The problem is, we've since changed our minds.
-- democratic socialist