God I love Bartok. When I played piano in high school I basically only played Bartok and Brubek.
I think people find unfamiliar music difficult to listen to. I don't think it's really about genre or artist.
I suppose some genres are trying to be difficult on some level (rock and roll, punk, metal, and rap each took up that mantle) but all of those were meant to be easy to listen to for a target audience.
Bartok never struck me as super combative. Brainy, perhaps.
Yes, I agree with you about people not liking the unfamiliar. My comment was tongue-in-cheek. Though, you must admit, badly played Bartok is gruesome. My daughter plays violin, and discovered his 44 violin duets and also the Hungarian Dances suite. Luckily she is good enough that it is fun to listen to. But my standard joke is: "All teenagers seek out music that will drive their parents crazy. Mine found Bartok."