I also think there are some false presumptions going on in this thread:
When you "reserve" a seat on an airline, you are not GUARANTEED that seat. Even if you reserve the first row aisle seat to get off that airplane the fastest for a connecting flight, you have no right to that seat. The airlines make that very clear when you book your flight. You are not entitled compensation if they move you. You have no right to due process over the fact that the airlines move you. The seat does not belong to you whether you reserved it or not, it belongs to the airline and they can do what they want with it. What you are "guaranteed" is a seat on that flight, and even that is only a guarantee is quotation marks because they can overbook, and they can cancel flights, though are you are at least entitled compensation if they choose to overbook and boot you, or you otherwise are unable to board the plane because of the airline.
So, if an airline like Delta determines that they are going to bump someone else out of a seat so that my daughter with significant special needs is seated directly next to me, then I'm not being the rude, selfish, uncaring person who "robbed" "you" of your seat. I merely presented a problem *to the airline* and the airline resolved it as they saw fit to do so. They own the airline, they have the plane, they make the decision. I'm not "making" anyone do anything. Nor am I feeling entitled to something that belongs to "you" just because I have children. I have a logistical problem (a seating issue with my children). I approach the airline staff about my logistical problem. They solve it.
So,I really think it is inappropriate to discussing parents who do nothing but request customer service as if they running up and down airplane aisles "forcing" the rule abiding, seat reserving grown-ups out of seats they own. *Everyone* is following the rules here--- the parents who request seating help, those who reserve seats in advance, those who sit in the "family section", those who end up in the emergency exit rows and on and on.
Any one who has a serious problem with the rights, responsibilities and rules that govern seating on an airplane needs to take it up with the airline that they fly, not berate their fellow passengers as if they are doing something wrong.
:heart
While I don't disagree with your point about the fact that all your ticket gets you is A seat on the plane, it is a different kettle of fish when you are discussing the airlines that charge for advance seat selection. Delta is not one of them. However, for the Airtrans of the world that do, the person paying for the seat does have some ownership of the seat and the airline will not move that person.