Regarding the Russian curling doper, the argument I heard on the radio was that curlers still have to train as there is still a physical element to the game. If you get tired you'll get sloppy and you'll be less accurate, so you train so you don't get tired during a game. Doping means you don't have to train as much.
But, yes, this seems to be more of a mistake more than anything else (a single dose of heart medication meldonium allegedly, and taken during the games too) but the doping rules are very strict and apply regardless of the sport involved. (It's the same drug that Sharapova was banned for in Tennis.)
Beta-blockers would be a far more sensible drug of choice for curling.
Anyway, odd that the Winter Olympics is already over, I hadn't really got into it or watched much of it.