Lance Armstrong has rolled out on Tour de France roads and pondered why he is treated differently to his contemporaries from a drug-ridden era of cycling.
Armstrong's participation in Le Tour-One Day Ahead alongside former England footballer Geoff Thomas, who is aiming to raise £1million for Cure Leukaemia, has been a divisive issue.
Brian Cookson, the president of the sport's governing body, the UCI, said Armstrong was not welcome, but Tour leader Chris Froome understood the charity element, having lost his mother to a blood cancer-related illness.
Armstrong, who was stripped of his record seven Tour titles claimed from 1999 to 2005 before confessing to using performance-enhancing drugs, pointed to other convicted dopers who are still involved in professional cycling.
"Why am I not welcome? Because I'm a doper? If that were the rule, the caravan would almost be empty," Armstrong said on cyclingnews.com.
"I don't mean the riders in this Tour, but in the press room, the commentary boxes, team cars.
"We all rode in an unfortunate era. But if you're going to apply a standard it has to be universal."
Thomas is taking on the entire 3,360-kilometres route of the 2015 Tour one day ahead of the professional peloton to celebrate the 10th anniversary of entering remission and riding the 2005 Tour route.
Armstrong was his inspiration a decade ago and was invited back by Thomas to ride on the roads of the Tour.
The 12-rider group, including Armstrong, took on stage 13 from Muret to Rodez on Thursday and will tackle stage 14 from Rodez to Mende on Friday.
"It's nice to be back, yes," Armstrong said.
"I understand people's reactions. I understand there are still some hurt feelings and that's a process I'll walk through for a long, long time.
"Honestly, Geoff started a great thing. The cause is near and dear for him.
"He came to Austin and talked to me about what they're doing and asked me to come. He made a real passionate effort so I decided to do it."