This has been in my drafts for months. Just for completeness, I am still posting this (even though it is older than dirt now.)
WoW General Discussion – This was found in one of the forums. It’s in that pretty blue color which means it’s from an WoW representative, I think.
Apologies for the length of time it took to get this information out to you.
We encourage community building among our players with others of similar interests, and we understand that guilds are one of the primary ways to forge these communities. However, topics related to sensitive real-world subjects — such as religious, sexual, or political preference, for example — have had a tendency to result in communication between players that often breaks down into harassment.
To promote a positive game environment for everyone and help prevent such harassment from taking place as best we can, we prohibit mention of topics related to sensitive real-world subjects in open chat within the game, and we do our best to take action whenever we see such topics being broadcast. This includes openly advertising a guild friendly to players based on a particular political, sexual, or religious preference, to list a few examples. For guilds that wish to use such topics as part of their recruiting efforts, our Guild Recruitment forum, located at our community Web site, serves as one open avenue for doing so.
We will be clarifying some of the language in our game policies in order to help avoid such confusion in the future.
Reading this response makes it clear that Blizzard isn’t stopping the guilds from forming. It just prevents recruitment inside the game via open chat.
This may be sensible and I think I agree with this.
Another link is here: Blizzard apologizes for GLBT guild warning | News.blog | CNET News.com