Yep, if you're good you have a doctor. If you're really good, you have the really good doctors.
If I recall, the first EPO test came off the back of research by a guy (Conconi) who was at the same time doping athletes to the gills. So when it came in, everyone already knew how to beat it. Effectively for these doctors they truly think they're doing the right thing. They are improving the "health" of athletes through pharmaceuticals. And maybe they are...