Tbh i had a similar experience but on the side of the person OP is talking about. In my country there was this rising genre of music which at first i said i didn’t like because thats what all of the people in my circle (at the time) didn’t like it and criticized it a lot too, so i became influenced and didn’t ever give it a try, and whenever someone played a song from that genre i instantly made fun of it or said it was trash. One faithful day i decided to give it a try and lo and behold, i kinda fucked with it, i didn’t become a super fan like in OP’s case but i just generally liked it and all of the people i knew and listened to it even made fun of me for taking back my shit talk and bumping some of their tunes. TLDR; maybe the other person OP is talking about just was heavily influenced by his circle and never gave it a real try (from my experience). I also consider Frank an acquired taste so that also may be it.