It’s not. Forums users can flag forum posts and if there are enough flags, those posts get hidden. The author of the post can then edit it or leave it as it is until a forum moderator decides whether to restore it or delete it. That’s the short explanation. You can read the long explanation here if you’re interested.
That’s the “how”. As for why people flag posts, it’s because it shouldn’t be too hard to disagree with each other or with Funcom without resorting to shіtty personal attacks and name-calling. And indeed, it’s not too hard for most of us. I’m not shy about posting criticism of how Funcom keeps screwіng up this game and I don’t get “censored” for it, along with a ton with other people.
But every now and then you get someone with the schoolyard bully mentality who thinks that insults like this are really funny and smart:
That’s from the dude who has to keep creating sock puppet accounts because he’s never had a single valuable thing to contribute to the discussion. And when his verbal excrement gets cleaned up from these forums, he then comes crying about how he’s getting censored.
Long story short, if you can keep it civil, you most likely won’t get flagged. And if you do get flagged despite that, you can edit your post to reword it and it gets unhidden. Nine times out of ten, that’s the end of that and everyone’s happy. Occasionally, however, someone abuses the flagging feature and the mods might get involved to restore your post and deal with the false flaggers.