DETROIT — Pistons coach Dwane Casey wanted to establish a tone on the first day of training camp, his 28th edition of the annual two-week preparation period leading up to the regular season. “No excuses.” Those two words were displayed on Casey’s gray shirt to serve as a reminder that even though the Pistons have a youthful roster, pulling the inexperience card won’t be an acceptable excuse when it comes to competing on a nightly basis. “This is an unforgiving league against young guys, and it’s up to us to go and take it,” Casey said. “We can’t sit back and use ‘young’ (as an excuse). That’s …