Because he wouldnt command the support of Black Leaders, who until Obama had been loyal supporters of the Clintons.
If you mean they've commanded the support of the party machine (which involves 'black leadership') - yes. But that's because the Clintons were, in the '90s, controlling the party, and from 2006 on, Hillary was the ascendant Presidential star.
But there has certainly been no love lost between, say the Congressional Black Caucus and the DLC (which is
the Clinton stronghold, obviously). When there have been challenges to the Clintons and their wing of the party, "Black Leaders" (I really enjoy treating 'those people' as a monolith...) never lined up in support for them.
And he would have been just another inexperienced noob from Chicago.
All politicians are "inexperienced noobs" - right before they become players. No one has presented - race aside - any reason that Obama wouldn't have made that leap.