Walters aside, who was offered more money by another club, all the players you mention were Agar signings who wanted more than RS / GH were prepared to give them (be that in contract length or other conditions).
It wasn't so long ago we were complaining about players being retained on too long contracts. The club has decided to draw a line in the sand. It's not great for this season, but Austin could have just played out his current contract and acted more professionally. If anything his behaviour vindicates the club's decision not to give him a longer deal.