Both Kanye West and Justin Bieber have taken inspiration from classic heavy metal teams for the merch for their respective tours -- Yeezus and Purpose -- and fans of the genre have had mixed reactions.

Shepard Fairey, both an artist and a huge music fan, is infatuated with band merch, and thus has some pretty strong opinions on who has permission to both wear and appropriate it. Bieber is guilty on both counts, as he has been wearing Metallica shirts and the like at recent concert appearances, on top of using the aesthetic for his tour shirts.

"If Justin Bieber really is a fan of Pantera, then more power to him," Fairey says, sarcastically, in an interview with HypeBeast. "But I'm not a Justin Bieber fan, I don't care what he does. I will not allow Justin Bieber to taint an entire genre for me."

Fairey goes on to display his collection of vintage band tees, which include pieces from proto-punk outfits like The Velvet Underground, The Modern Lovers, and The Stooges. "If you're going to wear a band tee, you'd better know that band," he says, cringing as he recalls a woman he encountered, who wore a Joy Division shirt but admitted she didn't know the band.

Later on, he touches on Kanye's use of metal imagery, which he's strangely more on board with than Bieber's. "Kanye has a history of smart samples in his work," he says. "The idea that he picks and chooses the right raw material for the things he's doing, I can respect that, as long as it's remixed creatively. If Kanye's choices of subcultural things to appropriate means that it leads people from him to those bits of subculture that might be undiscovered otherwise."

Watch the full interview below.