#Because non-D&D players aren't generally non-experts

The Stack Exchange network is generally designed from expert Q&A. This means I don't need to explain the basics of the stuff I'm asking about to you, or explain where it's from if that's obvious. I can just ask my question using whatever jargon is appropriate and wait until someone with the appropriate expertise answers. On our site, this is still how non-D&D questions work. If I talk about the combat resolution system for Dogs in the Vineyard, I don't need to say stuff like "Okay, so, you roll dice equal to your two attributes for the combat mode and then you...": I can assume you have or will RtFM and if you haven't and won't, that's your problem, not mine.

Similarly, for questions, if I ask a good question, I only have about a 70% chance of people with 0 experience getting mad because I didn't give them the links they want to make an easy extremely-low-quality answer. This chance is low enough that the downvotes and close votes are, at least for me, worth the offputtingness that hopefully discourages answers from people who have only ever played the latest edition of D&D and don't have particularly great reading comprehension skills from grabbing a pdf of the rulebook off the internet and either throwing out whatever their first guess is after ~10 minutes of work or posting a stock 'ask the DM' answer with 0 system-specific investment.

These two things are not true for our 5e D&D community. There's also a subcommunity that likes editing to link everything in 5e answers to D&D beyond stuff, which looks like but is not usually supportive citations.

Also, our 3.5/pathfinder has a sufficient group of highly-active really good users that you usually get a good answer to your question eventually (though it may be buried beneath highly-upvoted or accepted nice-sounding absolute garbage), and part of how that subcommunity works involves writing like this. That looks like a wall of citations (which is not a complaint!), but it is actually mostly not that. The only real substantive citation in that (totally fine) answer is the link to the errata for the DMG supporting the claim that there isn't any. The two "see here"s contain an appropriate joke emphasizing the community's eternal struggle with D&D's love of reusing words and a q.v. onto another tangentially related topic the author had previously treated in some detail. The rest of the "citations" aren't support for the answer-- they are assistance to the uninitiated in looking up basic information in the books. Like, the answer tells you the ring of protection is on page 232 of the DMG, which it spells out in full. That's because you might not know what 'DMG' means, and you might-- even though you are currently reading a question about the ring of protection and it's a totally normal core magic item in the core magic item section of the DMG-- not know where to find the published statblock for the ring of protection. We write that way not because it supports the content of the answer but, at least for myself, because 1) it forestalls some complaints by people who haven't read the material 2) it gets more upvotes 3) it looks/sounds cool 4) it is more helpful for educating and helping the audience than not doing that.

There is no requirement to attach non-supportive citations to your answers. As far as I'm aware, no other subcommunity on this site does that, though 5e is superficially similar and I'd write similarly for SR4 if I were answering similar questions nowadays. There is a requirement to Back Up your answers, and the current top answers on all the questions you link do that. They just don't hand-hold you to every page and book (note also that most non-D&D systems only have one book) on every topic mentioned. They expect you can look it up yourself if you want to.

Props to @KRyan and @HeyICanChan for developing our unofficial 3.x writing style.

I think this answer is kind of rant-y currently. I'm not sure how to make it less rant-y. Any edits helping with that would be appreciated.