Yes, yes & yes. If you have an "invisible illness" which so many are, you will also simply not be believed. People will give you a hard time for eating an alternative diet, avoiding cake, avoiding alcohol, or judge you for being weak and it all stems from fear, as you so eloquently point out. It's the same reason we shun elders: fear of aging and death. Societies have long had rituals, traditions and institutions to honor elderly people, perhaps to counteract this fear of aging, but we in the US seem less willing or able to cope with the reality of our own mortality.