I am guilty of having been using the boards for 3-4 years and only just read the rules... 30 seconds ago.
These points are paraphrased by me
It says they can ban your smurfs too for coming to the boards after a permaban and claiming "I already have 10 banned accounts I just keep trolling".
Endgame spoilers would have gotten removed back in the day too :D "no spoilers"
No provoking conflicts or baiting people, which also seems like the average fun post to read
And the #1 rule is no being disrespectful, which... I think all of us are. "I hope you step on a lego you... jerk!"