Re: 12 Monkeys pilot greenlit by Syfy
Presumably so he won't interfere with their activities in the past. It was implied that the time traveler "volunteers" lose their minds and eventually "don't come back." The street preacher may be an example of one who's "gone rogue."
That was my point. How does his interference matter if you can't change anything? Why is a time traveler going rogue a problem, when they can just send another one?
Just walk away, and there will be an end to the horror.