Asking for money is fine. Negotiating hard is fine. Holding out with two years left on your contract rubs me the wrong way. Turning your back on the owner who supported you during the tough times feels like an act of betrayal to me.
Between the owners and the players union, the league is organized to screw rookies on their first contracts, and thereby in particular elite RBs, who, unlike other players, have their best years consumed during their rookies contracts. We were quite open about using up Murray on his rookie contract, and then tossing him aside, and hoping to do the same with Zeke.
The NFL and players union used their power for their benefit. RBs are starting to use their power to hold out for their benefit.
People apply their notions of contract developed from their experience to a contract context very different from their experience.