surely that would also apply to people writing new tunes and songs then? it's no different - that's just a pretty way of rendering a some words/notes & if that's nice then why shouldn't people take it on and enjoy passing that on too?

so if I sing a song that somebody else wrote and don't give them any credit, thereby making my audience believe that I wrote it myself, that doesn't matter?

If I wrote a song and somebody else wanted to perform it, I'd be chuffed to bits. But if they passed it off as their own, I might be a bit upset! Is that unreasonable?