I can't believe he is catching so much heat for stating something so obvious (well, I can believe it, but what I mean is it seems kind of crazy).
I mean, if any athlete has their coach suspended for 4 years for doping violations, then that athlete goes out and runs one of the craziest doubles of all-time - doesn't just win, but wins outrageously - isn't it kind of a no-brainer for people to be suspicious of that athlete? I don't give a rat's ass about Sifan Hassan one way or the other, but I'm personally suspicious of her purely based on simple reasoning skills.
And I don't know Nick Willis at all. But supposing he is clean, put yourself in his shoes. How would YOU feel in the late stages of a long career during which your successes were always limited by dopers? If nothing else, this is a guy who got bronze (at first) in an Olympic 1500m in which both runners ahead of him were later popped for doping. Doesn't the guy have a right to a little skepticism?