XBL's auto-censored word list was (and maybe still is) wild. If you have any PC ports of Xbox games from around the 360 era, there is a chance the plain text file that contains the list is in the installation folder somewhere (IIRC, Dark Souls Prepare to Die Edition has it). Bans were usually automatic if you had any of those words anywhere in your profile, and it included "gay."
You also couldn't put shit like "Halo sucks." You could put "Mario sucks" or "Sony sucks" but any disparaging comments about Bill Gates, Microsoft, or any of their IPs would result in an error.