He's factually correct - seems reasonable to assume Nene would have been a player with interest from other clubs. He has not downed tools like some other players, and because of the broader situation that has led to him not being able to play. Not Nene's fault so I see no reason to object to what Rowley said?
With regards to Sam Stone, refusing to play unless you consider it to be a beyond usual risk to your health (i.e. you're carrying an injury already) or you've not been paid (he has been, admittedly with no small amount of stress) is not reasonable. To do so on the day of the game when a squad has been set and there's no scope to bring in a replacement is just unprofessional.
I'm a Salford fan and have no issue with any player seeking new pastures under the broad circumstances, but there are ways to go about this that are more professional. Several players have left this year and will always be welcome back at Salford (Sneyd, Singleton, etc.), others have embarrassed themselves.