He never walked up to the guy and said that (like smokers even say things like "dude, I had this great dime bag last night" in the first place), it's more of a "if you're doing your job well we don't care" statement on the part of the manager. Unless you work for a company that does weekly drug tests or something like that, it's probably the unspoken policy everywhere.
And also, would you be more accepting of an alcoholic simply because it's legal?