Nah, that's where you (and Rock with his Starsky & Hutch comment) fail to address the real point. Starsky and Hutch are white. They're white characters who were written to be white. Same goes for Johnny Storm. Saying it ain't historical drama is bullshyt, it's historical that these characters are white. Now times may change. For instance, a black James Bond, while still no reality, seems closer to the possibilities, but even that is largely because James Bond is reinterpreted with every actor that plays him.
But the point I think Rock was getting at, and I agree with, is that people can perfectly relate to characters of another race if they're cool, so there's no need to make all of them white, or always pair up a black man with a white man just to make sure audiences aren't turned away from how 'black' the movie is. But even then, we've seen movies disproving that notion (Bad Boys is a famous example, a buddy cop movie that breaks the boundaries of the oh so typical black guy/white guy pairing and was very successful) and Hollywood fails to take notes from it.
Back to his criticism about Starsky & Hutch (or yours about Johnny Storm), the problem isn't that there's a common idea that established white characters can't be portrayed by black actors, the problem is that there aren't enough black characters given shine to, except for the occasional token stereotypes, and too often roles (of original characters) are offered almost exclusively to white actors and not black actors. That's something he also addresses, but he gets off point a couple of times rambling in different directions when that's really the big one.