people are free to poison themselves if they want to. they are also free to have another opinion than you do. if someone disagrees with you on a health matter, it doesn't mean they are blind and willfully heading off a cliff and sure to come to imminent doom and destruction. it just means they disagree with you. i think you should, in your heart, give people more permission to disagree with you than you currently do. you will feel much better about things.
also, when you say "i don't get emotionally involved in debates" - this is not true. the feelings you just expressed in your post demonstrate that you DO in fact get emotionally involved in curezone posts and curezone issues. if you weren't emotionally involved you wouldn't be feeling frustrated right now. and thats not necessarily a bad thing, it just shows you are passionate about these issues. so perhaps acknowledging the fact that you are in fact emotionally involved, and then seeking to be less emotionally involved by letting go, will help.