I think they meant he should not be returning kicks from 5-6 yards in the end zone to only reach the 22 when he could have taken the touchback and netted the team a few extra yards.
But all that return yardage adds up and looks good on your stat sheet when pro bowl voting begins, and I imagine every player has a Pro Bowl bonus in their contract, so good for him.
Maybe so, but I seem to remember people saying he was too valuable as a receiver to be used as a returner. In that case, I think the coaching staff was right on t this one—you let your best returner do what they do best.