Yup, your talking to a wall.
Been using additives in my fuel as long as I can remember with great results. Better fuel economy, add's to lubricity therefore prolonging injector/pump life, removes the water from the system, reduces combustion chamber and exhaust valve deposits, etc...
If they are a placebo how do you explain documented MPG increses? How do you explain ASTM bench test results that show decreased injector scuffing? How do you explain injection pump manufacturers like Stanadyne releasing TSB's that show that lubricity additives increase pump life? Let me guess, there's no such thing as global warming either.