So any exceptional performance warrants suspicion and innuendo of PED use... oh right unless they ride for a Brit team.
Not at all but the facts here are the guy is 42 years old, he's from a nation that hasn't produced a clean GT contender in thirty years, and he regularly hammered PED abusers in the States for years during the height of the doping era. Therefore, logic is used to make my sad conclusions. Nibali's comments post stage yesterday seemed to suggest he was thinking along similar lines.
At least if you are going to state facts, make them correct, rather than exaggerated, rounded 'caricatures'. Horner is 41 years old, even if almost 42. As for who was the most recent clean U.S. GT contender, I'm not sure who you are counting. Lemond winning a GT in 1990, 23 years ago, and contending to some extent (7th in TdF) in 1991. Hampsten winning a GT in 1988, 25 years ago, and contending (4th place in TdF in 1992), 21 years ago. Or is Lemond out as not clean? Was Hampsten doping with anti-freeze on the Gavia in 1988 Giro?
Also by your logic, Wiggo couldn't have been clean, since GB had most recently produced a TdF winner, NEVER. And then the same would have to apply to Froome, as Wiggo wouldn't count, as he wasn't clean per above logic, As for your logic, Mr. Spock you're not. That doesn't mean that Horner is clean, but merely the illogic of your logic in determining him to not be.