In the same way, if you told someone you had cancer would they say "Are you going to die?" or are they more likely to ask "Is there any hope for you" or "Is it curable?" etc.
For me, maybe it's the connotation that infers someone has 'passed over to the other side', which I don't believe in.
It's whatever gives people comfort isn't it.
My mum and dad, both long dead (sorry, passed) NEVER said Passed when they meant Died, never said Poo unless they were talking to us as little children, and the word Wow never EVER passed their lips.
Just read this and agree with bainbrig. I cannot stand the new fad for saying 'passed' , not even passed on or away.
I told my kids they can say die, or any eupemism like conked out, popped her clogs, shed this mortal coil, anything but if I ever heard them say passed on/away/to the other side, I'd come back and make life hell for them.
I used to live in London near Abney Park Cemetery, where William Booth, the founder of the Salvation Army is buried. On his tombstone (in the shape of a badge) it doesn't say he 'died', or 'fell asleep' or 'passed away' - it says : PROMOTED TO GLORY
Death is a difficult subject and people speak of it in whichever way that makes them most comfortable. Some are flippant, some dour, some concerned at the prospect of offending. Personally I always say quite straightforwardly that someone has died, but however others want to express it is fine by me.