I think it was after I was listening to meme songs when I was a kid (Carameldasen, Nights of nights, U.N was her).

I then listened to stuff like Triple Baka and Levan Polka (I don’t remember which one came first).

But yeah then more vocaloid stuff got recommended to me, I got more familiar with Hatsune Miku and Vocaloid, then I checked out more Vocaloid songs.

Basically, it was thanks to memes.