There's a lot of bad everything: Roger quite rightly drew attention to Sturgeon's law – that 95% of everything is crap! However, the OP asked about bad street photography, so that's what I'll comment on...
To paraphrase the OP:
"The vast majority of so-called 'street' photography does ... not exhibit any degree of photographic merit, often they don't have a subject and look like a haphazard, random snap. Poorly framed, out of focus, people looking down at the ground."
(1) This presupposes that a "good" photograph is the opposite to the above: well framed, in focus, etc.I get that. A photograph, like a painting or any other picture, needs to follow some kind of aesthetic or it's just a random collection of shapes. Photographers obviously have it easier than painters in this regard because a camera can automatically create a representation of reality without input from the photographer. I'm not going to open the can of worms labelled "composition" – but I will point out that we've developed a visual grammar over the centuries that helps us understand and relate to pictures – just as we have syntax in language. It's knowledge of this grammar that's important, not its slavish application.
It's worth noting that just as grammar in language varies between countries and even communities, so too does visual grammar. That's why Japanese street photographs often look so different from Western ones, with the former tending towards symbolism and the abstract as typified by
Daido Moriyama.
Anyway, I'm sure we can broadly agree that a "good" photograph is "well composed" if it uses visual grammar.
A lot of photography is taken to meet a Western "pictorial" aesthetic: you can see this approach in nearly every landscape or portrait photo, for example. The Taylor Wessing Portrait Prize gets flak every year because it's looking for a contemporary postmodern take on art rather than the traditional – so you get photographs that people with a preference for pictorial art decry as "boring" or "deadpan" because both the content and visual grammar differ from their expectations.
Anyway, the kind of landscape or portrait photograph that appeals to most people depends mostly on aesthetic qualities borrowed from the look of old European paintings. Usually, its appearance is prized more than what it means or is of. I'm sure we can all picture the kind of thing...
(3) Photographs don't have to be "art" – they can be record shotsA purely documentary photograph is only about information. Perhaps it shows a person's appearance on a driving licence or the cake mum made for little Susie's sixth birthday. Aesthetics are of no importance. A snapshot is all about how well it shows us something – whether its composition is "good" or "bad" is immaterial. You may like well-composed photos better than, say, my mum's awful wonky snapshots – but that purely personal preference has no bearing whatsoever on the success or not of my mum's documentary photography!
If anyone is wondering where photojournalism fits in, I consider it akin to street photography, and to rely equally on content and aesthetics.
(4) Which brings us to street photographyStreet photography is exceptionally difficult: way more demanding than, say, a typical landscape photograph. It depends for success on two aspects: documenting information in an aesthetic way. Moreover, what it documents and how are very specific. For exactly why street photography is difficult, see point (5) below.
Anyway, this means that most people are rubbish at street photography. I certainly am! Also, since street photographs are both artistic pictures and social documentary, "bad" street photographs are either all about composition and document very little, or the opposite – they document people or social interaction well but with poor aesthetics. As others in this thread have pointed out, many people are fascinated by what are essentially snapshots taken on the street simply because of the social documentary aspect, so slack is cut for bad street photography because of the subject matter.
I've heard it said too that because street photography can't be controlled like studio photography, "flaws" are acceptable. I don't buy that! I can't imagine Cartier-Bresson or Meyerowitz saying: "But it's an excellent photo of you ignore that annoying arm, and had I been standing a couple of feet over so that bloke didn't have a tree coming out of his head!"
Anyway, I think the reasons for mediocre street photography being praised are because it's so tricky coupled with our affinity for seeing pictures of social interaction.
(5) What is "good" street photography?I'm going with what most people – and Wikipedia – define street photography as: depictions of everyday life in public places made through a specific approach. The aesthetics of street photography owe a lot to Cartier-Bresson and others who pounded the streets during its seminal period from the 1950s to 1970s: Winogrand, Friedlander and Meyerowitz in the US and Ray-Jones and Parr in the UK, among many others. There are variations on this theme: I've already mentioned the abstract symbolism of Japanese street photography as typified by Daida Moriyama. But let's stay with Western street photography.
Cartier-Bresson called his photographs "picture-stories", and said that they were of "the fleeting moment when the apex of the occurring action coincides with the other graphic elements within the frame to create the best possible composition" – his decisive moment. He was very specific about what he meant by "apex". A lot of street photographers are doing street photography
wrong! Judging from their photos on the web, many mistakenly think that this apex is the point of maximum "action" – when, say, the girl kisses the boy. A picture has only one frame, so showing an instant
other than the "main event" may communicate more clearly what is happening. Let us return to our amorous couple – would a picture of them a moment before the kiss, eyes locked on each other, lips parted, not quite touching, tell us more about their passion than the kiss itself? Or maybe the moment after, longing and desperation apparent as they part, perhaps forever? The street photographer's apex, then, is a moment chosen so that what has already taken place, and what is about to follow, can be most easily understood, and we can see the present, the past and the future.
That's just the "what" – a street photograph also requires perfect aesthetics! Remember, Cartier-Bresson said that the decisive moment was not just the story-telling moment but also the moment when the "best possible composition" occurred. Cartier-Bresson was a painter, so he knew about composition.
This decisive moment may have been a new departure for photography but it has been depicted by painters for centuries. Here's an example:
Orpheus and Eurydice by Rubens (about 1636). There is a tale in Greek mythology about the musician Orpheus, who was permitted to take his wife Eurydice back from death and the underworld on one condition: that he walk before her and never look back until reaching the world of the living. But he looked back ... Rubens painted this myth not at the instant when Orpheus turns his head and Eurydice returns to death but before. Rubens’s avoidance of the "obvious" moment imbues the painting with drama and increases the sense of narrative: we see Orpheus and Eurydice leaving Hades and Persephone, but he is grim faced, struggling to keep his eyes off his wife, and we sense things aren't going to end well; in our imagination we embark with him on his journey towards the light, pitying the couple as we anticipate their tragedy.
Painting the decisive moment is one thing, as the artist has full control over what appears on their canvas, photographing it is another: the street photographer not only needs an eye for a picture and technical skill like the painter, they require luck too – to be in the right place at the right time!
Orpheus and Eurydice, Rubens
