[coldtea]

Some do it because others are offended if they see them in full print.

Others do it because in many places you wont pass moderation without it.

[solarkraft]

I'm more offended by having to guess which word is meant.

[latexr]

It doesn’t matter what the word is. It’s [expletive], it’s grawlix, it’s whatever swear word you want, in whatever language you speak.

https://en.wikipedia.org/wiki/Grawlix

[ghusto]

I don't think I'm alone in reading "they ** up" as "they fucked up" in my head, without meaning to. So whoever would be offended, is still offended, only now they can't complain about it since the person technically didn't swear.