Well, of ocurse, it is not discrimination from a legal standpoint. But, I think you are missing a bit of perspective in your post. Just because it is easy for YOU to do something, you need to realize that other people are differently situated.
Like, how does an infant use an umbrella stroller? And what about twins? Or kids that are close together in age (perfectly spacing out your kids is not an option for a lot of folks for various reasons)?
Not to mention, we have a "largish" double stroller that lies completely flat when folded. Whenever we have taken it on a plane we not only fold it down, but put it in a special carrying case to protect it. Really, it's not causing a burden to anybody and the plane has plenty of room in storage for it.
Finally, I think you are being too generous by claiming this is not about money. It is ABSOLUTELY about money. Maybe, you could make that claim if airlines were not now also charging $25 per checked item, but this change will result in millions of increased fees to the airline.
How is it about money when the airline is
exempting checked strollers from baggage fees?
There seems to be an assumption in this thread that AA is doing this for money.
I was curious what American said about the size of strollers and
see that they recommend not traveling with large strollers because of the possibility of damage.
"Large Stroller or Non-Collapsible Stroller or Heavy Stroller Weighing Over 20 lbs.†
Strongly discouraged to avoid damage. Facilities were not designed to accommodate these types of strollers
May be checked at the ticket counter†
May not be carried on the aircraft
Exempt from baggage charges
Please note: American is not responsible for damage to any stroller not properly packed in original packaging.
†Effective June 1, 2011, large, jogging, non-collapsible strollers, or those over 20 lbs will no longer be accepted at the gate and therefore must be checked at the ticket counter. There is no charge as long as a child or infant is traveling."
The size of the gate checked strollers has been getting bigger and bigger. In the past, not as many people flew with strollers and most of the strollers were smaller. I did have a very high end umbrella stroller for my kids when they were little - even as infants - it had back support built in.
And Maclaren strollers were invented in 1965, so not all strollers in the past were huge.
Since many people want big strollers that fully recline and have double cupholders, that is what many companies are making. But, the price for those conveniences is size, although there are strollers out there with the convenience that are small and light.
I spend time on the end of the jetway every flight getting my DD's wheelchair broken down and folded to be taken down the stairs for loading.
I see the strollers that are left at the gate. They may look small to the person who is using them, but they look huge to me and I am comparing them to the size of a narrow adult wheelchair. Some of them are as big or bigger when they are folded than my DD's wheelchair when it is not folded.
One or 2 of those kinds of strollers are probably not much trouble, but I have seen the gate baggage people struggling to deal with them. And, especially to Orlando, there may be 10- 15 of those big strollers on a flight.
I saw one get frustrated trying to carry one down the steps because it was too wide to fit. He finally gave up and chucked it off the side!
I have seen posts where people complain that it is hard to carry their stroller onto the bus ( only up a couple of steps at most).
Imagine carrying that stroller up and down a steep set of fairly narrow steps all the way from the gate to the ground.
I feel for the parents who want a stroller all the way to the gate, but I can also see the airlines side when the strollers are huge.
God forbid a 3 or 4 year old have to walk. 
I can understand why some restrictions are necessary - we looked at a few single strollers that weighed 40lbs and folded up would have taken most of the cargo space behind the back row in my minivan - but a little common sense and consistency would be nice.
