I grew up in a household where it was often emphasized that bad language is immoral.
That is, it somehow reflects on a person's character, or even controls it.
Recently, I entered a place where vulgar language was common currency. People talked about the more delicate segments of human anatomy with a flippancy that would never be acceptable in most of my social circles.
It was weird, because I was enjoying the company of the people making these comments, and their words didn't seem in particularly bad taste because they treated each other with kindness, consideration, and an attitude of servanthood.
Unfortunately, my first impulse was to harbor a strange guilt. I shouldn't be okay with the way they're talking, I thought. It should offend me. It should make me uncomfortable.
The thing is, it did make me feel a little uncomfortable. I don't think at the root that it's respectful to talk about someone's anatomy without regard to their personhood. I think that talking this way is indicative of more deeply rooted attitudes that come out when the person speaks that way.
But what I realized is that language does not control the character of a person. It may be in many cases an outgrowth or a symptom of that person's character, but you are not going to change who they are by objecting to their use of certain words.
It has always struck me as really pointless to label certain language as "bad." As a writer, especially as a poet, I understand that every word in every language can be used to convey effectively something that is important - or it can be used to convey clumsily something demeaning.
So while I might believe there are certain uses of language that are not helpful (like maybe that downplay the self of a person in favor of commenting on their physical, emotional, or sexual significance) to anybody, I don't believe there are any words that are just "bad."