The game has a message, and does present issues such as segregation and/or discrimination in light of the setting (1912). However, I wouldn't consider it a game for kids due to the immense amount of violence thrown into the game. While the game does handle issues such as discrimination, the state of America near the turn of the century, and the personal morality of the central characters, the consequences of one's decisions, and so on, the level of violence is a pretty strong drawback. For older teens and adults, it can be incredibly inspiring, but just too violent for kids.
I disagree with the ratings on sexuality. There is a revealing dress that shows cleavage on a main female character, and there are people talking about the cute guys and girls to try dating, but it's generally far more casual and discrete than what most teens are exposed to nowadays. Again, a reflection of culture back in 1912.
The main positive of the game is the focus on how the main characters' decisions and lifestyle affected himself and others around him, and how the consequences are there, a factor that many games don't include to as strong of an extent.
The high level of violence though, makes it a game for mature audiences.