Most top receivers want the ball, and Jones acknowledges that. Michael Irvin demanded the ball, too, and was in Aikman's ear. The focus of Jones' comments was on Dak playing within the system.
There's nothing wrong with pointing out that great players want the ball. That's a compliment to Dez and Witten. The key was Dak, as a young quarterback, can't let that pressure be a distraction.
If Jones had said something like Dez's poor route-running was the reason the passing game wasn't as good, that would have been a shot. This is a player and some fans being too sensitive when the team mentions a player that was cut. No one is jumping up and down saying that he's blaming Witten for Dak not playing as well as he did in 2016.