I guess I don't really have a problem with the idea that people that make a lot of money are greedy if they want even more of it, but that applies to both sides - labor and management. I just don't think one side should be viewed that way and not the other. Realistically, are the teams, the owners, and the NFL as a whole less greedy? Do they deserve or need the money they make?
For that matter, do you or I? How do we place a value on what someone does for a living? I'm sure a lot or people in low paying jobs would think I don't deserve what I make, and I could certainly live on less money, but I'm still going to get whatever I can. And really, that's the idea capitalism is built on - if a person works hard and excels at something, they can make a lot of money. Of course, that applies to businesses as well. Dollars are a big driver for both sides.
Something to remember too, I think, is that skyrocketing player salaries didn't just happen by accident, nor did they happen without knowledge or active involvement from the teams. The first time a team agreed to a $25 million/year contract, they knew that would start the price moving to $30 million, and they knew the first time a team agreed to $30 million that would start things down the path toward $35 million. So the teams were very much a part of creating the environment.