How am I wrong? The link you posted states "The minimum age to rent a vehicle is 21 years of age." Sure there's a $20 a day extra fee, but that's negligible in comparison to the inconvenience of not being able to rent the car. The sentiment of my comment was that you don't have to be 25 to rent a car.
You replied to a comment stating that rental car companies picked 25 as the age below which people don't always act like adults actuarially speaking. That bet is a literal charge in this case, weighing loss of business from higher prices against increased risk of loss from un-adult behavior.
You said that is not true in Tennessee and, as I explained, you are wrong about that. While I'm sure you knew what you meant, given your lack of explanation it is assumed you were directly replying to the central tenet of the previous comment (i.e. that persons under 25 are less adulty and should be treated as such).
You're right. "ramraj07" was arguing that the rental companies view under 25 year olds as less mature, not that rental companies won't do business with them. That's where I went wrong.
Of course no place bans renting cars for folks under 25, but the point is they don't consider you a regular adult at that point, more like a risky adolescent.