Every time I read a post like yours, I think "Do you really want to treat HIV with a placebo?" But I know that's an uncharitable reading of your position. Which diseases do you propose be treated with placebo primarily?
All I said was try a placebo and see if it works as part of the standard routine. Obviously with a potentially fatal illness you want to use everything in your disposal to stop it. Why would you not use your last resort for something that serious? But then that includes using both physical and psychological treatments. If someone has HIV then the boost that positive thinking delivers to the immune system (http://legacy.lclark.edu/dept/chron/positives03.html) combined with anti-virals could save a life. If it's something like, say, depression or migraines or the flu, then a placebo may well cure it and there's no need to prescribe drugs which have nasty side effects or are addictive. If you can get something for free, why would you not do it?