Good idea...
I will point out the following though, before the lock.
1. The rules of UO do NOT prohibit people from basing a guild or other in-game community around a common religious belief in RL among its members. In fact, the rules, as written, go the other direction, and make it clear that harassing people in-game for their religious beliefs is illegal.
2. Truthfully, there is little difference between people getting together for a prayer meeting in a house in Luna, or using any other avatar-based chat system for such communal behavior.
3. The only real issues should be in the persons confining such out-of-place behavior to within their meeting house, and their methods of advertising their group. Off-topic posts in forums is fine, as is word of mouth in private conversations.
On the other hand, such activities such as streetcorner preaching in-game and broadcasting via comm crystals in pets to public places, not only tends to break the canon (let alone the fourth wall - like many even give that any mind any more) of the game, but tend to draw more ire than new membership.
4. Lastly, a lot of the hostility towards such groups, to me seems to come from persons who are known for their long-term Felucca or Siege Perilous residence (or at least that being their preferred gamestyle).
Perhaps I'm reading too much psychology into it, but it almost seems that the real source of the trouble comes from the critics never actually having a guild or circle of in-game friends where things like TRUST and generosity were not only not issues, but an integral part of the guild belief systems. Think of it as the "Grinch syndrome"; where, never having experienced an in-game organization where charity, cooperation without direct reward, and lack of greed were the baseline norm, resent them when such a group (religous based or otherwise) appears, because they personally believe that nothing ever happens without secret motives, and that no one can ever trust anyone in game.
Sure, this means that groups operating on such priciples sometimes get betrayed by someone faking their way in, and in the end, the "victims" are the ones that help each other put it in the past, often pitying those that felt the need to do such things.