Because it makes me happy.
Before I was into kpop my usual favourite genres were punk, metal and fairly hard rap stuff, with a very odd side order of Taylor Swift and Disney songs. But the punk/metal/rap stuff was my main.
Started going through a rough patch tail end of '19 and came across Blackpink and found listening to them when I was in a crappy mood made me feel happier and upbeat, where my usual angrier music obviously kept me... angrier. With the absolute insanity that was 2020, I got more into kpop and discovered other groups like Dreamcatcher, Gi-dle and later Itzy and just found that their more upbeat, happier sounds (even when singing "darker" songs) and getting involved in their non music stuff like silly youtube videos, comeback lives, community stuff just helped keep my mind out of the darker places I was going to in 2020 with lockdowns etc.
I still like my punk and rap stuff and listen to it still, but kpop is now my favorite genre because... it's generally just so "happy" and positive.