Wiggins, winner of the 2012 Tour de France, has said in interviews and written in his new book, Icons, supportive comments of Armstrong, who was stripped of his seven Tour titles after it was revealed he and his team systematically doped through each victory.
“I’m not saying he’s an icon," Wiggins said in an interview with TalkSport in October.
“Whether people like it or not he’s iconic in some way, good or bad.
“For me, I can’t change the way he made me feel when I was 13. It changed my life.”
In his book, Wiggins - who retired at the end of 2016 - wrote that Armstrong was a "perfect" Tour de France winner.
Thomas, who rode with Wiggins at Team Sky from 2010 until 2015, was asked about the comments while he was in China, riding the ASO organised Shanghai Criterium. The 32-year-old said it was easy for Wiggins to say such things now he is retired and away from competition and regular interviews with journalists.
"Brad's got a book to sell," Thomas said to AFP.
"He doesn't have to worry about anything, either. He doesn't have to race his bike and deal with journalists.
"He can just say what he wants and do any interview he wants so he can say something like that and get a load of publicity."
UCI president David Lappartient has also criticised Wiggins' comments on Armstrong, saying he found the "strange" and unbelievable, adding: "“In supporting Lance Armstrong who’s been banned for life for cheating, for me this isn’t acceptable."
In the same interview in Shanghai, Thomas also said he would be targetting a second Tour de France victory in 2019, riding alongside four-time winner Chris Froome. The Welshman acknowledged how difficult defending his title would be though.
"If you look in the history books, the last man to retain it after winning it for the first time was (Miguel) Indurain, back in 1991-92," said Thomas.
"So it kind of shows how rare that is."
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