That's one good thing about traditional singers of traditional songs. They pass on the songs, it doesn't really matter too much if they might be pretty badly flawed.

You wouldn't say "I can't sing that song - it was collected from that really awful person who'd done those awful things." It just wouldn't be relevant.

And there's a real sense in which people who make up songs and music are really just intermediaries, passing on something they picked up from the world around them., something that's been given to them. If something beautiful comes out from a person who seems totally evil, that's something to be thankful for. It's even a sign of hope for us all.

So maybe I'd make a distinction between songs and music that are just OK and songs and music that are beautiful.

As for what songs mean and coded messages and that - a songwriter might have one thing in his or her mind when writing it, but the song doesn't just mean that. Again if you look at traditional songs it becomes easier - who knows or even cares too much about what "the original meaning" of a song was. What matters is how it speaks to us today in our own lives.