Update (after almost two years):
Well, actually, swear words can be used with no problem if the intention is to enrich the answer, like, for example, when listing synonyms. But using them when there's simply no reason at all is plain unnecessary and in my opinion should be avoided.
Well, I'm not a mod, so I don't know if my opinion would change anything, and some (or maybe many) will disagree with my opinion. But, even though, here's my counter-argument about this matter.
In most cases the use/mention of such words is unnecessary.
Let's take as example some of the questions in which an/some answer(s) used some "unpolite" words:
- Diferença entre e uso de “Boa!” e “Bom!” como interjeições
- Why in Brazil “nossa!” (our) is “wow!”?
- “Ao mandar o Bernardo às compras…” Is this an idiom?
- Does “rapariga” have a pejorative connotation in ptPT?
- Equivalentes em português para a expressão “Bitchy resting face”
- Is it offensive to call a little boy a “putinho” in Portugal?
- Existe em português um equivalente a “freaking awesome”?
- How to use “zuar”?
Out of these 8 questions, in 5 of them (1, 2, 4, 5 and 8) the use/mention of vulgar language in the answer is unnecessary. I explain why.
In the first, the noun used in the quote could perfectly be replaced for another more adequate word and the answer's information would still remain intact.
In the second, the use of the word that was censored is both unnecessary and misleading, because there are two vulgar words that starts with a "p" and ends with an "a", and I wouldn't know which of them is referred to if I didn't read it here in this meta question. So instead of censoring it, I think it would be better to just remove it, as the answer is totally clear even before that part.
In number 4, the OP just asked if in Portugal "rapariga" is pejorative, but this answer also includes more vulgar synonyms, which weren't asked and the answer would also keep intact without it.
In number 5, although it is said that in Portugal this word is considered less vulgar than in Brazil, it would be better if used another, more "universal" word, like "bunda", or at least clarify in some way that the usage of this word is different in Portugal, so that people from other countries (mainly Brazil), could know why it was used, or linking to another question or text that explains the differences in usage and meaning, etc.
And in number 8, it's made in the answer a reference to a meme in which its name contains a vulgar expletive. It's just a reference, the answer wouldn't change without it, it's not the answer's core. So if the author really wants to cite it, it would be more proper to censor, especially because it follows a link to a page about it, so there's no need to be completely spelled.
The only one that would not be necessary to be censored or anything, is number 3, in which the word is not depreciative, in context, because in Portugal it has a completely different meaning. But in the answer there should be any way to tell for those who don't know that it just mean "kid/boy", like linking to a question or another source about this (as I did), or maybe use "menino" or "moço" instead.
And the feminine form in number 6 is necessary. Why? Although the question is about the masculine form, including the feminine form is important to prevent misleading people by making them think that the feminine form has the same meaning as the masculine. Also it is directly related to the question.
But the answers in number 7 are between unnecessary and necessary. The question asks about a Portuguese equivalent to "freaking awesome". "Freaking" is an euphemism. Euphemisms are intended to avoid using "unpleasant" words. However, out of 3 answers, only one suggested some non-vulgar alternatives, while the others suggested as many coarse words as they could.
I suggest we avoid using strong/vulgar/swearing language, unless the question is about or directly related to those words. If swearing have to be there, but is not necessary for the answer's clarification, I suggest it should be censored (with "***", or whatever other way). If the reader does not know the word, they will find it again in another place (swear words are never difficult to come across).
Note: I have no intention of "offending" the authors of these answers, I just used their answers as examples, but with no relation to who wrote them.