I’ve noticed that the Wikihow.com article “How to Appreciate Death Metal” suggests many of the same tactics we use to try to convince people to listen to classical music, especially post-tonal classical music. Learn about the composers/performers beforehand. See a live performance. Realize that not all of this music is the same and there are many subgenres. Appreciate the skill of the performers.
Ipso facto: what Deeds of Flesh and Schoenberg have in common is a position on the fringes of musical civilization that requires education and acculturation to fully appreciate.
(For the record, here‘s the Wikihow on classical music appreciation.)