You’re kidding, right? Listen to some of their interviews instead of just banging your head to their music. Their body art say it all.
No. I’ve listened to these guys for over 30 years. They’re not satanists. Maybe not angels but that doesn’t make them satanists.
You can go away now. St. Anger was terrible, and I’ve never been able to listen to any new Metallica since then, but I love the old stuff and would still go see them live.