If a more able bodied person is "better" still, I guess you're right, you / employers can be the judge of it; after all, no one would be so blatantly honest about discrimination, be it marijuana use or overall health... there's always another reason to give to a candidate or worker. I have to agree that I don't think more government regulation would help in that regard. But maybe that's based off of my apathy, lol.
Anyways, im hoping you can consider there are reasons to consume marijuana other than just getting fucked up. its not always a reflection of bad character or poor work ethic.