Disgraced American Armstrong, who has received a life ban from cycling due to compelling evidence of drug taking during his career, could also help clean up the sport, Roulston said.
"Lance was the best at everything in that era. Unfortunately that included doping. Not everyone doped, but a lot of the biggest stars did.
"Due to knowing this, Lance will always be my idol. He changed cycling then, and has now changed cycling again. Good things always come out of bad situations, and this bad light that's shining on cycling now will prove that."
Once the toast of the Champs-Elysees, Armstrong was formally stripped of his seven Tour de France titles and banned for life for doping overnight on Monday.
As far as the Tour was concerned, his victories never happened. He was never on the top step of the podium. The winner's yellow jersey was never on his back.
He might have cast a large shadow over the sport, but Armstrong had also done a lot of good, Roulston added.
"He came back from cancer. That can't be forgotten no matter what happens. Even if he loses everything, he has that," he said.
The decision on Armstrong's future by the International Cycling Union (ICU) marked the end of a drawn-out saga. The 41-year-old has always denied doping, but the governing body has decided otherwise.
"Lance Armstrong has no place in cycling, and he deserves to be forgotten in cycling," Pat McQuaid, president of the governing body, told AP.
"Make no mistake, it's a catastrophe for him, and he has to face up to that."
It's also devastating for Tour de France organisers. Director Christian Prudhomme said: "For us, very clearly, the titles should remain blank. Effectively, we wish for these years to remain without winners."
Armstrong's fiercely defended reputation as a clean athlete was shattered by the US Anti-Doping Agency two weeks ago, when it detailed evidence of drug use and trafficking by his Tour-winning teams.
The agency released its report to show why it ordered Armstrong banned from competition back in August. Monday's judgment was the necessary next legal step to formalise the loss of his titles and expel him from the sport.
- By Erin Tasker of the Ashburton Guardian
