Just to be clear, I am not joking or playing a character. I legitimately think a forum thread going off topic is exactly the same as a soccer game being interrupted for a picnic. I constantly see posts from people asking about a game on sale get drowned out by a bunch of "regulars" that want to argue about WWE or some random AV question. That's cool that you want to talk to your little internet buddies and no one else really cares, but I feel bad for the guy trying to decide what the best bang is for his $5 that's being ignored. Like, can you imagine asking for fitness advice on a fitness forum and even there no one wants to listen to you or help you out?
A couple things here. I think it's safe to say that if someone comes to this thread and asks for recommendations, they're generally going to get more than enough. I think what you're getting at is that someone shouldn't necessarily have to ask to know what the best deals. When a new deal is up the discussion about it happens and it only really is light if the deals are really bad or things have been on sale many times in the past. On a forum like this, if someone doesn't see discussion about what they're interested in they can either scrub back through the thread or PARTICIPATE instead of lurking and then complaining when they feel like the thread isn't acting how they want it to with no input (this is not aimed at you but at some of the people supporting your complaints who never otherwise post). As we've said before, there are several other places that are explicitly designed to encourage current deal ONLY discussion. TrueAchievments, Reddit (/xboxone, /greatxboxdeals), SlickDeals. If someone doesn't like or care about the community here, there are other options.
Personally, I think you probably would have more of an impact on this thread if you didn't keep posting about reporting people and instead focused on keeping the thread on topic with deal/game specific posts.
Finally, I think your fitness forum reference hypothetical is a pretty obvious type of thing that exists in a LOT of forums that have built up communities over time, and that our XBL thread is generally not guilty of this. The only time I see genuine discussion posts be ignored is if something has already been asked/discussed a lot recently, or if no on genuinely knows the answer or has an opinion.
One thought that I've had recently on this general topic is how CAG actually presents itself. Anyone that follows CAG's Twitter or Facebook is likely aware of the regular shitposts published about "deals" terrible PSN avatars or ironic gamer gear. I don't think this exactly promotes completely on topic discussion.