Ok firstly, suspending someone for weed is insane because that’s not a performance enhancing drug, if anything it’s performance degrading.
Secondly ask yourself why are they catching someone for weed but don’t catch all the obvious steroid use that literally every professional athlete does? It’s because they’ve intentionally made it possible to cheat their system and get away with steroid use, and the trainers and officials are the ones helping the athletes.
Watch the doco Icarus, the first half before it goes off the rails is all about how doping is an open secret and all athletes in all countries do it and their trainers help them