(CNN)Once again at the Tour de France, the spotlight shone on Lance Armstrong.
Surrounded by reporters and their microphones Thursday, the American made his long-awaited return to the roads where he won a record seven successive titles in cycling's most prestigious event.
But the 43-year-old, who was stripped of those yellow jerseys for years of "systematic" doping strategies, acknowledged that he was no longer welcome on the scene.
Tour chiefs had called him "disrespectful" for agreeing to take part in the charity ride, which tackles the race's 21 stages a day ahead of the competing riders.
"It's nice to be back, yes," Armstrong told journalists, as reported by Cycling News magazine.
"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."
However, he repeated past claims that he has been made a scapegoat in a sport where drug-taking was rife during the 1999-2005 era in which he was unbeatable at Le Tour.
"Why am I not welcome? Because I'm a doper? If that were the rule, the caravan would almost be empty," Armstrong said.
"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."
Armstrong, who famously overcame testicular cancer before winning his first Tour title, was taking part in the "One Day Ahead" charity event, which aims to raise money for leukemia research.
It was organized by former England international soccer player Geoff Thomas, who with Armstrong and 10 other riders took part in Thursday's 198-kilometer (123-mile) leg from Muret to Rodez.
"Honestly, Geoff started a great thing. The cause is near and dear for him," said Armstrong, who will also ride in Friday's 178 km 14th leg from Rodez to Mende.
"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."
Armstrong's return was not greeted warmly by some members of the Tour.
"You can ride anywhere @lancearmstrong but no trouble in your mind to steal media interest from riders like ours who never cheated?" tweeted the Bretagne-Seche team.
Former British cyclist Michael Hutchinson, who now works as a journalist, tweeted: "I greatly dislike the way Lance Armstrong is so clearly reveling in being back at the center of things on Tour."
Other Twitter users posted their online support for Armstrong, including one who reposted the Texan's picture of himself at home with his seven yellow Tour jerseys.
Meanwhile in the main race, Spanish rider Joaquim Rodriguez Oliver won his second leg of the 2015 Tour for Team Katusha in Thursday's stage 12 -- a rain-hit 195 km trek between Lannemezan and Plateau de Beille.
Britain's Chris Froome, the 2013 race winner, retained the leader's yellow jersey. The Team Sky star was two minutes and 52 seconds ahead of American Tejay van Garderen in the overall standings.
Two-time winner Alberto Contador -- whose Tinkoff-Saxo teammate Ivan Basso was ruled out of the race with testicular cancer -- was left four minutes and four seconds behind Froome.