The only official thing I can give you is the Stack Exchange Content Policy:
Hate Content, Defamation, and Libel. Hate speech and other objectionable content that is unlawful, defamatory, and fraudulent. Note that an allegation of defamatory expression, in and of itself, does not establish defamation. The truth or falsehood of a bit of expression is a key element in establishing defamation, and we are not in a position to make that sort of fact-based judgment. That said, if we have reason to believe that a particular statement is defamatory (a court order, for example), we will remove that statement.
Sexually Explicit Material. Accounts that use Stack Exchange to post sexually explicit or pornographic material, or links to it, will be suspended
These are the two relevant sections to this discussion. They are the only binding network wide restrictions.
However, the question should be raised: Should we have higher standards than the average stackexchange site? If so; What are those standards?
Personally I have moderated this site for the past several months (and I can't speak for the other mods, but I think this is where they are as well) on the following principals:
This is the Internet. The fact of the matter is that the Internet is a more offensive place than regular life, for a variety of reasons (all of the irrelevant to this discussion). But taking this into account, there is more leeway in content than in other venues.
We are not a church. In fact. We are a subdomain of a privately held, secular corporation. While we are a site about Christianity, comprised largely of people who claim to be Christians, we do not claim to be a church or para-church institution (quite frankly, no church would take us).
I'll know it when I see it. Content should be judged on a case by case basis. We can try to follow some precedent, but ultimately, content should be judged on it's own merit.
This site is and should be more restrictive than the general SE network. Because this site strives to be a place where all people who identify themselves as Christians should feel welcome, we should try to be a bit more family friendly than the rest of the SE network feels like they have to be. This generally isn't a problem on the site itself, but more often comes into play in chat (where we are more likely to warn someone about language/content/topics than elsewhere on the network). However, the same thought process applies to the site. This is not to say that we do not want to handle serious and potentially offensive topics (adultery, masturbation, swear words, etc), but we should do so in a manner that handles these topics with the levity that they deserve. We should be able to speak frankly about matters of sexuality and language without descending into juvenile behavior. Things that are obviously trollish, or meant to offend will be shut down immediately (and if the community wishes to disagree, save, edit into shape, that is (as always) their prerogative)
Wait for flags. Unless I find something completely egregious, I'm going to be looking for other users to identify content that is offensive/inappropriate. honestly there is too much content here for us to track every question and answer, if you come across something you find offensive, vote it down, leave a comment, edit it, and/or flag it. However, I will still follow the previous rule of evaluating the content on it's merit.
Now, let's address the specific case. I think it's a pretty crappy question, it starts with (what seems to be) a false premise, which is a red flag. However, I think it got answered fairly well and then was fairly quickly closed by the community. After the closure there are plenty of people around here with delete votes, but they elected not to use them on this question, obviously seeing the situation as resolved by just closing the question (and handing it enough downvotes that even if it's edited it likely wouldn't see the front page again).
Ultimately I don't have any problem with the deletion here, but in the general case we should let the community make those determinations, rather than stepping in as moderators (we have some pretty active delete voters, specifically for answers).
In conclusion, I only feel bound by the SE content policy, but will take into account that this is a site that is intended for "People who identify themselves as Christians."