If anyone thinks that the use of illegal drugs can be recreational or 'harmless', have a chat with your local MO [especially if he has had outside GP experience]. It does not take much to mind-alter to the point where individuals can develop serious psychiatric conditions. And very often they manifest themselves over a very short period of time, where it might not be picked up until the individual has harmed himself or does something catastrophic, like commit a serious servicing error.
Latterly, and after 30-odd years of service, I resented being drug-tested, until I realised that it was the only way to weed out the drug-takers. Then I tolerated the intrusion. As far as I am concerned, the present policy if slinging out the drug users is absolutely right - high as a kite and carrying a loaded weapon? Servicing an aircraft?
Roland was absolutely right - the lunatics really have taken over...