For one thing, many of the swear words/expressions cannot be translated, not even by using more than one word/a few words, there are languages where one can fill entire books with swear-words/expressions (one of them is Romanian, which I speak natively, I've heard the same thing about Russian or Hungarian) and there are languages where swear words/expressions are a lot less diverse (English is the example I know best).
Of course, one can try to naively translate the "băga-mi-aș pula în morții mamii tale!" into the English "I will insert my dick into your mother's dead people", but this naive translation doesn't (can't) catch the word inversion "băga-mi-aș" (from "mi-aș băga") which makes the whole action sound a lot more dynamic and direct in Romanian, plus the word "pula" has a lot more meanings and context in Romanian compared to the simpler uses of "dick" in English, and last but not least the Anglo world seems not to care about one's dead people as much as we Romanians do (and I think we're not the only ones), and as such mentioning some other person's dead close relatives in a derogatory way is seen at most as quaint (while "morții tăi!"/"your dead people!" in Romanian is oftentimes used as a swear expression all by itself, I know I use it frequently).
And this before we get to all the diminutives/suffixes that can be added to any word that is part of a swear expression (and not only) in a language like Romanian, a feature that is absent from most of the English language. For example the mentioned above example can very be easily changed into:
> "băga-mi-aș pula în morții mămițicii tale!"
with the "mamii" to "mămățicii" change (basically from "your mother" to "your little mother", where "little" actually means "more loved"/closer to the person being addressed) giving the whole swear expression a new other, even more personal feeling.