How did the street preacher know Cole was a time traveler? Or the bum who called him Bob? There seems to be some kind of unexplained connection. That aside, someone uncontrollable who knows their methods, objectives and when/where they're sending people could raise hell with their operations. The scientist-council said they had had a lot of problems with unreliable time travelers. They were also shown to be a high-handed, demanding, controlling and not very ethical group, so eliminating those who don't follow their program to the letter didn't seem too far out of character.