James Bond is an upper class British gentleman. I know the type; public school, Oxbridge then straight into the foreign office or the military. James Bond isn't black or low born. He just isn't.
Not quite-read the original books. James Bond is not posh, though he isn't "low-born" (by the way, the seventeenth century rang, it wants its horrid expression back). He has got a Scottish father and a Swiss mother and grew up abroad, making him unclassifiable and something of an outsider to the British class system.
That's the Fleming Bond. The film Bond can be anything the producers want him to be. In much the same way that people put on Shakespeare plays with e.g. black and Asian actors in whatever roles they fancy.