This is to clear a path for me, to let them know to get out of my way, and also so that I don't have to smell too much tobacco stink when walking by those people, as they are standing there and puffing on their cigs. I have found that this method works well!
I have found that ex smokers who psychologically beat up on present smokers eventually learn some humility.
Unfortunately, they usually hafta learn "the hard way."