This discussion may contain spoilers!
Long story short, I just picked this game up a week ago and played through it in a few days. It was exceptional and I liked it a ton. This is actually my first post.
Getting back on topic...I was kind of surprised to see that hardly anybody killed both of the St John brothers. Upon finishing episode 2, I noticed that only something like 18% of players chose to do this. While the St. Johns looked like they were good people before the world turned to shit (minus Danny - he seemed odd from the beginning), they obviously threw whatever principles they had out the window in the name of survival.
These people were literally surviving by trapping unsuspecting travelers and feeding off of them. They even had a system in place to keep captive travelers alive through the use of morphine and various other medical supplies - so they could continue feeding off of them. As Danny put it, you didn't want somebody to become "tainted". On top of that, they even had special rooms set aside for the specific purpose of harvesting human beings (the back of the barn and secret room upstairs).
Apparently this system had been in place for some time as well. This is evident by a few things:
It had been going on long enough for the St. Johns to make some kind of protection arrangement with the local bandits. This deal revolved around the St. Johns giving food to the bandits in order to keep them at bay. Seeing as how the farm only had 1 cow, it seems as if they were giving away human flesh. This theory is backed up by Jolene (crazy lady you and Danny find while looking for a bandit camp) saying something along the lines that she knows what the St. Johns have been doing.
After seeing David (Ben's teacher) get trapped on a random bear trap in the beginning of the episode and later seeing Danny fall to the same kind of trap, it became obvious that the St. Johns were responsible for laying that trap as well. Why do I think the trap was sprung for humans and not animals? It had been modified in such a way that there was no release mechanism on it. You wouldn't need to remove that part if you were just trapping animals.
So after the shit hit the fan with Mark and after putting all these things together as the story progressed, it was an easy decision to have Lee kill them both. I honestly felt like that if I left them alive, whats to stop them from trying to do this again to somebody else? They had obviously lost any kind of morals and decency by the time this situation played out.
So what did you do and why? And just for a frame of reference, I didn't just have my Lee going around killing everybody like Rambo or something. I actually tried to save Larry, let Lilly stay in the RV after she snapped and killed Carly, and pulled Ben up when he wanted me to drop him. My Lee was very much a pragmatist with a strong sense of situational ethics.