I think the reason we hold our breath or mention what someone might be on is simply because so many of the people we watch anymore. Pro sports, college sports, even High School sports. We have secreat deals that will allow someone to race in olympic events as a woman who may or may not be a woman by DNA tests to baseball players coming out after years of denial and confessing to doping.
Lance is tested just about every time he rides and has come up clean yet the question persists even in cycling circles. The question just pops into your head even if someone is just naturally more talented than everyone else. We all hope our favorites are clean but no one is really surprised when they discover another one has failed a test.