I'm torn on this example.  I see what you mean, and I agree: swearing or other "harsh language" can definitely have a deleterious effect on a sentence, but I think that the second sentence is ultimately missing something that your first draft of it *did* have.  It seemed more grimy, more real. Maybe finding another way to say it without using such a strong word like "piss"?  Maybe something about the acrid scent of cats they could taste in the back of their throats?  Something like that.  Just a suggestion.  Probably wrong, but I wanted to see what you thought of that.

-Ken