why did BHO seek the votes of racists, etc?

And I'm having a hard time telling the substantive diff between his effort and Bernies, since neither suggested/hinted that they'd be attending any KKK rallies.

Bernie ---- "Many of Trump's supporters are working-class people and they're angry, and they're angry because they're working longer hours for lower wages, they're angry because their jobs have left this country and gone to China or other low-wage countries, they're angry because they can't afford to send their kids to college so they can't retire with dignity," Sanders said on Face the Nation. http://www.commondreams.org/news/2015/12/28/sanders-makes-play-trumps-angry-supporters

BHO ---- On February 12, 2008, Barack Obama mentioned Obama Republicans in his Potomac primary victory speech: "We are bringing together Democrats and independents, and yes, some Republicans. I know there's—I meet them when I'm shaking hands afterwards. There's one right there. An Obamacan, that's what we call them." In another speech, he said, "We, as Democrats right now, should tap into the discontent of Republicans. I want some Obama Republicans!" In his call for Republican votes, Obama referred to Ronald Reagan, who he says "was able to tap into the discontent of the American people...to get Democrats to vote Republican— they were called Reagan Democrats."
RepublicansforObama.org

RepublicansforObama.org was founded in December 2006 by John Martin, a US Navy reservist.[4] The organization grew to include over 2,500 registered members from across the United States, and was featured in USA Today, The New Yorker and other media throughout the 2008 Presidential Campaign.[5][6][7]https://en.wikipedia.org/wiki/Republican_and_conservative_support_for_Barack_Obama_in_2008