Even though the percent might not be much higher, it's really about turnout, not percent won. Twice as many blacks showed up to the polls for Obama than for Clinton. Obama was a "movement" candidate in the black community.

However, I'm sympathetic to your argument - I think blacks turning out for Obama was more akin to Irish Catholics showing up for Kennedy, rather than whites showing up for George Wallace - more of a pride thing, and a symbolic triumph over past discrimination, etc.