Real question here, I know I only come on here to troll the trolls but...
The Rohrabacher Blumenauer Amendment only protects Medical MJ. So Session's could have been going after Recreational MJ at any time, but he hasn't. What make you think this amendment is protecting anything? If Session's were to crack down on MJ it would most definitely start with recreational which is already unprotected by the amendment. If he were to attack Medical he might as well commit political suicide.
So why is this even important? If Session's attacked the MJ industry he would start with an attack on recreational, not medical...