WWE can't be seen to have a lax attitude towards an illegal drug, especially after their previous version of the Wellness Policy was publicly revealed to be a joke. There are bigger drug issues to be tackled, but WWE have to be seen to be strongly against all illegal drugs. Now, whether they let some guys slide when it comes to using those drugs is another issue.
Yeah, but when the media gets on the WWE's case about illegal drugs it's usually in regards to stuff like steroids. Wrestlers smoking weed? Who gives a shit? That won't sell you newspapers or bring in the TV ratings.
The government pays attention to, you know.
The government barely even cares if NBA players are smoking weed before games, so I would be surprised if pro wrestlers, who get already get away with god knows what, are smoking up beforehand. It would seem to me like WWE management would have bigger concerns to deal with, such as pain killer abuse and what would (reasonably or unreasonably) be considered "performance enhancing drugs."