I get why you would say it wasn't worth keeping. Because it came from Jenner's point of view, at the time he was trying to make them understand why they should all want to kill themselves along with him in the decontamination.
If Jenner was trying to argue his point, then it made sense for him to have told all of them to try and reason with him and get there is no hope because everybody is infected. For Jenner it shouldn't have mattered and he should have just said it, he had given up and was trying to get the group to understand why, he should have told them all.
The only reason I can get is because the writers wanted a hook for viewers tbh and back in the day, season 1, nobody knew.