Why did Heck Tate and the men with him want Tom Robinson moved out of the local jail?

Heck Tate and the men around him want Tom Robinson moved out of the local jail because they are afraid that he will be lynched. At this time in the south, mobs of white vigilantes would sometimes take matters into their own hands and kill African-American suspects by hanging them from a tree. They did not wait for the alleged criminal to be tried in the criminal justice system. Lynchings were particularly common when the suspect was accused of raping or accosting a white woman, as Tom Robinson has been.

Heck Tate is eager to remove Tom Robinson to a county jail for the night, but Atticus believes that there won't be any trouble of that sort in Maycomb. He tells Jem that there has never been a Ku Klux Klan in the town, and Atticus believes that no one will harm Tom if Tom stays in the Maycomb jail until his trial.