Some may suggest: "You only think discrimination is "wrong" if it's directed at you."
If through some study, argument, test, a child of 10 who's physically proportioned for the task of operating the switches, levers, pedals and gizzies necessary to operate an automobile, isn't that sufficient? Isn't the fact that this child qualifies through his/her size to be considered capable of operating a motor vehicle? Or is this single criterion but one of many that qualify a candidate for testing that could lead to driver licensing?
And it's not sufficient in and of itself
because it is but a subset of the greater set of skills and abilities that contribute to judging the prudence of granting the driving privilege. Potential candidates for licensing are required to demonstrate many other skills as well... The capabilities of this individual with respect to their manual dexterity, their hand eye and over-all physical co-ordination, vison exam, a familiarity with and cognitive ability to internalize abstract concepts for example. And there exists a plethora of analysis from many different fields and separate disciplines within those many fields that argue that a ten year old simply hasn't lived long enough to be expected to consistenty intuit synthesize and understand critical information in the paragidm of dynamic incessant modifications to conditions...that operating a motor vehicle is.
It's reasonable to apply these standards to the qualification process of eager young drivers because to permit them the control of a vehicle in busy traffic , failing weather conditions and spontaneous mechanical failure....without satisfying these qualifications they are more likely to result in their and potentially other peoples catastrophic outcome.
Elderly folk who choose to continue to drive their vehicles, sharing the roadway with many many others, have a responsibility to acknowledge to themselves that their safe operation of a motor vehicle relys on a broad spectrum of conditions and abilities. It is prudent for society and for the individual to require driving proficiency tests when age injury or disease reduces anyones competency.
Stands to reason.
The "moral" injustice suffered by the young the middle aged and every demographic you'd care to name, is everyones responsibility and if the few dollars less that a senior needs to purchase a movie ticket or a bus ticket or whatever the circumstances might be....if that's as a notion at the top of the pile of injustices and unfairness foisted on you by the world.....trust me, you're not doing too badly.
Whine if it makes you feel better...that's what children do.