I think that some of us may be looking into the subject too deeply - I believe that 90% of the street shots of Homeless People are basically a 'free pass' into "look, I'm evoking emotion from the viewer!" by non-creative People.
Quite a lot of subjects are a 'free pass to evoking emotion' : a weeping child, a smiling bride, a doleful dog or any cute furry animal.
Which leaves only formal landscape and abstract composition as acceptable subjects for a serious photographer. Can we still do nudes, or is that also too facile?
It is a bit easy to tar the whole genre with the brush of trite sentimentality. Yes, some of it is easy sentiment, and some is lazy street photography. But a lot of photographers sincerely want to share their shock and empathy at encountering scenes of deprivation and abject poverty. And I suspect those who would dismiss these photos as pain porn, would rather not have to deal with the problem at all. I can understand : poverty stinks, literally. Talking to a three weeks unwashed homeless drunk with vinegar breath is not my idea of pleasant conversation. It would be nice to just look away, pretend there is nothing to see. But if we all keep looking away, it will only get worse.
Of course, a photo will not better the life of a homeless subject. But sometimes, photos do move public opinion , and sometimes, public opinion moves governance.
I know, small individual acts will not change the world, but, as the chinaman said : 'Every little helps', while he was relieving his bladder in the yellow sea.
Cheers