Adam, without getting into the ethics / moral issues / legal issues surrounding street photography, let me throw some thoughts at you regarding the image you have posted.
The first thing that strikes me about this shot is that you really have two separate images in one shot (with two subjects)
1.
2.
A. Having two subjects tends to be weak compositionally as the viewer's eyes tend to flit back and forth between the two subjects. This is generally not a good thing.
B. The lighting conditions you were shooting under are quite harsh. This means harsh shadows and bright highlights which makes it much more difficult to pull of great images.
C. Your choice of aperture settings and focal length have resulted in pretty well everything in the image being in focus. Shallow DoF can help simplify the image by softening the background. This is the one reason I like doing street photography with a full-frame camera while shooting wide open with a medium telephoto lens for this type of shot.