While I can appreciate the annoyance when people take a discussion off-topic, in a threaded forum like Reddit, you always have the option of just clicking the little 'close' button and collapsing a comment and all of its children. This is really the beauty of threaded comments; it lets people have their sidebar conversations in detail, without permanently dragging the discussion there. Everyone else can just continue to respond to the comment upstream of the derail while interested parties hash it out. (Without this, you end up with something like Metafilter, where there's a huge amount of active moderation and fairly severe community-norms-enforcement, much of it aimed towards keeping discussions on track and dissuade trolling / derails.)

And depending on the context of the conversation, I can totally see why placing "the Bible" and "interview question" in the same sentence would attract attention. My internal HR-department DEFCON meter just went up about two points just thinking about it, and I'm certainly less attuned to Bad Ideas than most. I'm not sure that's a reasonable thing to expect people to just leave alone, particularly again when you have threaded discussions so there's not a ton of social pressure against nitpicking.

Reddit does have its share of problems, but given their apparent goal of being sort of the heir to Usenet in terms of an everything-to-everybody discussion platform, rather than simply a subject-specific discussion site, they seem to do rather well. I sometimes think they're insane and hubristic for the whole "platform" ambition, but they're one of the more successful attempts around right now.