The midfielder quit the club this week to join Jackie McNamara's side and fans have hit out after the youngster was allowed to slip through the Gers' grasp.
Boss Ally McCoist was keen to keep Telfer at Ibrox and DJ reckons the 18-year-old's decision has been influenced.
He told SportTimes: "If your contract is up and you don't want to be at the club, fine. Rangers don't want people that don't want to be there.
"There is no doubt he is a talent, but that is all he is just now.
"If he doesn't want to be at Rangers then what else can Ally do? He has offered him a contract and he has said no.
"I think his problem is the people who advise him. His dad wasn't happy with Rangers not giving him games.
"If it was down to the kid, I think he would have stayed where he was. Just because gaffer Jackie McNamara is playing youngsters does not mean he is going to go up there and go straight in and play.
"It might take him a year or so and if that is what he wants to do, fine.
"Ally had no option. If the player says he doesn't want to sign then you need to let him go."
Just days after Telfer headed to Tayside, McCoist made his first signing of the summer with the capture of striker Kenny Miller.
The 34-year-old's return to Ibrox has been met with a lukewarm response from the Light Blue legions.
But DJ insists experience will prove crucial for the Gers as they bid for the Championship crown next term against the likes of Hearts and Hibs.
He said: "I don't mind playing kids, but they have got to be good enough.
"You can't throw them in just for the sake of it, they have got to be good enough to play and deserve it.
"Lewis Macleod and Fraser Aird have proven that they are and they will feature again next term, as will Calum Gallagher.
"You can't just play kids because they are kids. They have to be ready.
"If you put them in and it doesn't go well, their confidence can go and it is hard to recover.
"It is fine playing for smaller clubs, but this is Rangers, there are huge crowds and huge pressure on you and you have to be able to handle it all.
"There are a lot of factors that come into it and I think Ally is doing the right thing.
"There are some good kids at the club and they will get their chance, but the priority has to be getting out of the Championship."