I have never found a 'why' question offensive.
Sometimes, whilst in the muddle that is shock/horror/fear, if I've been asked a 'why' question, that in itself has been a support because it makes me take a step back and take breath--and realise that it would never have done any good to rant at the world anyway--you get a grip on questions which can, might, or never will be answered.
And those of us with shameful habits/lifestyle know full well anyway what has caused/contributed to our disease.

Brenda