You’re right!
We should totally allow people to threaten others (remember that while on most forums “what’re you going to do, capslock me to death?” is a JOKE, on here, magick works at a distance, so a threat can be genuinely intimidating, and harmful even if not followed-through), something with added spice since this IS, after all, a black magick forum where death curses can be freely discussed. 
And also, I realise having actual conversations is dull, we should permit anyone who wants to, to spam the forum beyond useability so the entire index page looks like a big billboard for unknown randoms, and abandon all attempts to encourage people to be civil, because i bet that will lead to some quality conversations in-depth about spirituality, when “FUCK YOU LOSER” is the default for someone who has no reply…
What the fuck were we thinking having rules?!
@Timothy? @E.A?!
Face.
Meet.
Palm! 
Okay serious answer: as @DarkestKnight says, up to April 2014 this forum was behind a registration wall, not open to all as it is now, and it was barely moderated, the only time you’d see moderation would be if someone was threatening others, then the admins jumped on that quickfast.
It worked for a while, it was pretty comfy, but then as soon as we had one main person who was trying to spam, and aggressively derailing stuff (just one, mark you) the forum rapidly became unusable, it was like that sucked all the air out of the place, and ALL other conversations kind of ground to a halt (or got derailed, usually with stuff relevant to this problem-guy) and it was touch-and-go.
The admins brought in structure, moderation and rules, and while I miss the old wild west days, for a forum this scale, there is just no way we could dispense with the rules we have, which are anyway kept as close to minimal as possible.
All rules beyond that original thing of stopping spam and aggression have been in response to a genuine problem we either encountered often enough to need a rule (like the 90-day probation before free readings, which is long enough to keep people who have been banned for harassment, from offering readings to get into their taregt’s PMs again), or because of wider internet trends (the no-politics rule, which the admins felt was necessary).
If you want to pick out any rule and ask why it’s there, I can tell you. 
Imageboards are lightly moderated (only for truly illegal shit) BUT, people don’t use names and personae on those, so there’s no comparison: pretty much everywhere else is moderated alongs lines that have made sense to their own admins and so on.
But removing rules opens exploits that would end this being a forum where people can discuss any manner of magick without worrying about harassment, or finding anything worth reading in an ocean of spam, and therefore, although it may seem contradictory, having the rules we have grants more freedom to express oneself.