So what Ville is saying there is if you ask the band for permission and they grant you the rights to use the logo, they don't charge you a licensing fee. So Bam asked if he could use it and they said "Sure, go crazy. Do w.e. you want." However, if you don't receive permission and you are selling goods with the logo, that would be copyright infringement.
Example: If Lego wants to make a Star Wars Lego set. Lego has to seek approval from the rights holder i.e. Disney. If Disney says yes, Lego produces the toy and Lego receives all profits directly from sales. The way Disney makes money from this deal, is they charge Lego a licensing fee of some kind. Usually it involves a sum of money up front and then possibly residuals from sales.
So, I still stand by OP that I'm 99% sure this clothing brand, Ragged Priest, did not seek permission. It's sadly fairly common practice for fashion industries to blatantly rip off designs without seeking permission and therefore saving a ton of money in licensing fees.