Uncle Tom had an inferiority complex towards others. He was very submissive and always behaved like he was willing to accept his faith. His only strength was his willingness to believe in God despite all of the hardship he endured until his death by the hands of Legree´s men. He did manage to change the attitudes of the people and positively influence them into setting aside their prejudices and becoming Christian.
On the other hand, the Harris Family refused to accept their faith and decided to risk it all and embark to Canada. This led them to encounter the slave trader Tom Locker, who ends up injured after fighting with them. He is also, in a way, induced into setting aside his prejudices as he is assisted and taken to a Quaker settlement to recover.
Answer: By keeping facts like his name and the crime unknown to the reader, the reader can better visualize themselves in the position of the narrator, leading to more fear.
