Why doesn’t Cooper just explain to Lucy why shouldn’t help the tunics?

Cooper knows why the members of Legion aren’t worth saving and they will lead Lucy back to a bunch of people who will do unspeakable things to her so why doesn’t he just tell her this?

My guess is that because he was going to kill them and is only stopped from killing the slave woman because of the rad scorpion the reason he doesn’t just explain the situation to her is he realizes that Lucy, being the helpful person she is, would try to help the slaves escape which would be another unneeded distraction. It would take a lot less time to just kill them and explain it later.

Considering the slave women is so brainwashed that she doesn’t even try escaping and goes back to the legion only to be killed I’d say they were probably beyond help anyway, not that Lucy wouldn’t try.