Would you also deny others pain-relieving medication?
See, your philosophical stance is admirable. In my mind, thinking of pain as a positive thing is a healthy approach to life. What I find deplorable is forcing your personal view on others. That is pure righteousness.
Indeed, righteousness is the underlying problem here. Taking one's personal views on life ('... a crucial part of the human journey ...') and believing they are a universal truth. Once this belief is formed, the natural conclusion is to force others to live by it, because it is the Truth.
How about we let everyone decide what to do with their own lives, as long as they do not inflict harm on others?
Only I don't. But how does it felt? Do you really stoop to being so low a human being as to wish BS upon other people because you disagree with in a discussion?
Do you think that makes you better than whatever you think he is?
I do not merely disagree with his position. I consider it vile and a threat to me and everyone I know. It is one of those positions where compromise is immoral. Some disagreements are not matters for civilised discussion if you actually believe in it, slavery, religion, gay rights, morality in other words.
I feel just fine about wanting an end to Alzheimer's, to aging and senescence in general and I feel equally fine about wanting him to live out his beliefs about how suffering brings meaning to life.