I can’t speak for Grant Circle, but I live right off of Sherman Circle. I guess I have two thoughts on this.
1) I definitely see people speeding in, around, and near the circle, but I don’t get the impression that the mix of traffic, families, pets, children, pedestrians, bicycles, etc. presents any particular problem there that isn’t also present in countless other neighborhoods across the city. In other words, I don’t see why government officials would necessarily be persuaded to put speed cameras there rather than anywhere else. This is not to say I’m okay with speeding in my neighborhood, I just don’t get the sense that it is worse, or somehow condoned by the city, around Sherman circle.
2) I have absolutely no problems with speed cameras and I would be just fine with it if they put them in my neighborhood. There are a couple spots where they would sure make a bundle of money, if nothing else.