In a perfect world - casting could indeed be colorblind. The film "Cloud Atlas" did an incredibly brave attempt at it: It had black actors playing white characters, white actors playing asian characters, and asian actors playing white characters. It was an attempt.
But in reality, this issue is SO laden with intentional and un-intentional racism, it's a very hard topic to discuss. The problem with blackface is not that it's a white actor playing a black character. It's the whole stereotyping and demeaning beneath it. There's simply not going to be a "realistic" portrayal of a black man, if a white man directs another white man on how to "black" properly. An actor is not better because he can speak proper (white) mid-Atlantic movie dialect. How anyone can not see this honestly baffles the mind sometimes.
Also, if white people wouldn't just throw everytime a black actors play a traditional white role SUCH gigantic shit-tantrum (idris Elba being "too street" for James Bond, or the backlash of him playing Heimdall), and if we actually had a FEW black people behind the scenes, as directors or writer actually making decisions on how to portray black people on screen, the topic could be debated much more sober.
As it is, it's a minefield of shit-bombs. And we're years away from people being forgiving about mistakes with this topic.
Given the people involved, I am pretty sure ‘too street’ basically meant ‘not convincingly posh enough’ which is still pretty odd. I actually don’t think Idris is a good fit for bond, would have liked to see Colin Salmon working with Brosnan Bond more, and if I were casting Bond, would be auditioning Adrian Lester, as Hustle proved he would make a rather good Bond.
Basically Bond is a Brit character, and I suspect casting a black British actor as him would be less of a problem with the general populace here than people seem to think. Poor old Idris though, I dunno when he became the only Black Actor In The Village....though Hollywood seems to think so. Admittedly, I also think Lester would be a good Doctor Who, though I can also see...gah...I forget his name. The original Marquis De Caraíbas, he would be an excellent Doctor.
Basically I think it’s possible that some of the silliness around Idris as Bond story is basically nothing to do with race. Mind you, there was a hoo hah around Daniel Craig’s casting....and I don’t think he was well cast myself *shrug*
What can you do? I keep coming back to the problem being Hollywood itself tbh.