Hmm. Yeah, former CX world champions don't know a thing about peaking/winning or bike handling, the other thing that is helpful in the Northern Spring Classics.
The opinion has some validity. It won't be the first time athletes have good numbers in training, beating some, the getting destroyed by dopers within the month.
On top of that, we know the UCI, at best, has limited anti-doping resources. But it is more likely there is much more going on about Hein/Pat managing positives. It was tried with Contador, it was accomplished several times with Wonderboy.
As a general comment, shouting down the viewpoint there might still be doping issues is dangerous since we have so little anti-doping information to work with anyway.