The American cyclist, who survived testicular cancer, announced last night that he will not fight against charges accusing him of taking performance-enhancing drugs from 1996.
"There can be no other interpretation," Fahey told ABC Radio. "His failure to rebut the charges allowed the USADA to take that as an admission of guilt and to impose sanctions.
"I would have liked to see the accusations, the innuendo, the rumours that have been going round for years tested in an open tribunal and a proper process, whatever the outcome was, so the whole world would have known what the facts were."
Armstrong's decision could result in the 40-year-old being stripped of his seven Tour de France titles.