^I'd go so far to say that most people would find the tweaking actions of someone in the midst of a meth binge revolting and frightening, much more so than someone nodding off in the subway.
I agree with you, though. The US is the "land of opportunity," where if you have the determination, and capital to get your idea/plan off the ground, you might have a real chance at becoming financially comfortable. You can't chase the American "dream" if you're in a nod all day, and to the tax payer, you ain't shit if ya ain't chasing that dream. Little do they know that people they interact with on a daily basis can be opiate users, albeit not obvious ones.