"I think most people, even those who created these policies, would prefer a workplace populated by groups 1 and 2."

The people that created the policies... sure. Most people? Why? I have no problem with current drug users. Silicon Valley is chock full of semi-regular to regular pot smokers. And who knows how many take a few hits of ecstasy or mushrooms at their annual Burning Man or Coachella outings. You really see this as an issue? To be honest, I actively prefer to work with these people. You wouldn't have hired Carl Sagan?

As long as it's not affecting the quality of their work, why do you even care?