I think you missed the point. The brilliance in To Kill a Mockingbird is the way it makes us feel the confusion felt by a six year old looking at an adult world.
At the time, many people did see race relations as 'black or white', and people thought there was a perfectly legitimate debate to be had about whether someone that was black was 'less of a man' that someone that was white. What Scout really shows us is that children are not born with this pre-conceived notion, and are generally confused by it... and we should be too.
To address your specific points: the black people were not supposed to have much of a voice in the novel, because black people didn't have much of a voice back then. There wasn't much insight (in terms of speeches or things said) around race relations, because to a six year old girl the insight doesn't matter. All that matters is one of fairness - that a child cannot fathom how crazy adults must be to not give black people a voice or to treat them differently, just because of their skin.
PS: In response to your comment about Finch, you're right. Finch is perfect - because he's Scout's father - and most six year old girls do think of their father as perfect; if Scout hadn't been written that way then her character would have seemed shallow and wrong.
PPS: I've clearly thought about this too much and what I've wrote seems a bit preachy - as with any book, it all comes down to personal taste.