mvoight

Actually, it is not Standby.. It is Same Day Confirmed Flight Change and if even as a Platinum elite, I would have to pay for it
That is different than standby, which elites get for free, but is not a guaranteed SDFC means you can make the change in advance.
As a non-elite, you are eligible for SDFC, but not "standby". That said, the fee has been around for years and other US domestic carriers are similar.
Edit: I can see that the $75 in this case was what the agent might have called standby, but in any case, standby is not free for non-elites.
You are being charged a fee for convenience, for the reason is AA knows people will pay it. It isn't much different than other fees AA has. I am considering a change to my Alaska Airlines trip, but AS will charge the person going with me $125 plus the fare difference, yet, I am still considering it. AS will charge me only the increase in fare, about $40 for that segment,because I have MVP Gold Status. Airlines charge for better seats for non-elites. It doesn't cost them extra to provide them, but charges a fee because some people will pay it.