no, thats a common misconception, u.n. owen was her? is composed by ZUN , the creator of touhou. there was a video, in which someone plays this song on the piano. Someone uploaded it as death waltz, and now the half of the people that know touhou, think its death waltz. If you have questions, PM me, no hate. :D
Clearly you have yet to even play this game. If you play the game and go into,'music room' you won't find 'Death Waltz', you will find,'U.N Owen was her?'. John Stump's,'Faeries Aire and Death Waltz' is a piece of artwork made of random notes and was never meant to be played, when it is played it sounds like someone smashing their head on a piano.
Sorry for the very late reaction, but what you hear in the video isn't the deathwaltz. That video has the wrong info about the song. The song played in that video is an arrangement of u.n. owen was her?, which is played in this video as well. The real deathwaltz is a weird drawing of notes, i can give you a link if you want.
japanese is a nationality, not a race also, you don't have to view everything negatively; many japanese people take this as a compliment because it says that they are skilled and able enough to conquer the games that they make infamously difficult; obviously there aren't only japanese people who can completely decimate the game, but it's still meant to be taken as praise... sorry if you're japanese and offended, but i don't think the original commenter had any hostile feelings