I don’t know that Catholics even agree on whether or not it is immoral to
say a swear word, let alone listen to one.
I’m no fan of crass language. I never developed the habit and it usually makes me uncomfortable to hear it. But I’d be hard pressed to call it immoral to listen to a song with swearing in it just by virtue of it containing this or that word with no other considerations.
My music collection is pretty much all heavy metal, but I can probably count on one hand the number of CDs I own with any foul language on them. And most of the time, the word is there for a purpose.
Their are vulgar songs with no swearing in them and non-vulgar songs that do contain some swear words. I would pay more attention to the over all level of vulgarity than I would to the inclusion of one of a handful of words.