Why do people and parents not understand death metal as an art?

So i have recently become a fan of old school death metal particularly the band Death. i love their music so much and find schuldiner to be extremely talented, so i asked my dad to order me a Death t-shirt and i know my moms going to freak out and make a big deal about it. So before they harass within a few minutes.. how do i convince them the death metal is music just like any other, its passionate and musically genuine, and that the band Death does not use any obscene language or provoke violent imagery like any stereotypical death metal band would like they think. i swear my parents are obsessed with trying to get me in trouble for heresy and shiiiitt which is pathetic, possibly an exaggeration. what do i do? im so tired of holding myself back, they are so narrow minded.