Basically bungie has a kinda bot like program that tries to find words that get around the censors. The issue is normally when it gets a bit out of hand they reset it essentially. Though with Destiny's dev and security teams being basically a ghost town nobody can actually fix the issue and it just keeps expanding what words are banned. They know it's an issue but can't fix it.

"bad" words inside words. For example, lightBLADE is censored, as well as soMETHing.