For example...?
There may be one or two, but I think the vast majority of the images on this thread deliver on the subject line - thought provoking and anything but gratuitous.
I think it's worth remembering, too, that in an age before the internet - which is to say instant unmediated access to pretty much anything that's going on in the world - photojournalism was one of the few ways that important issues reached the public consciousness - and conscience. For just one example
is widely credited with having played a major role in ending the Vietnam War. Of course we don't need images to tell us that 'war is bad' - we knew that all along. But that 'knowledge' didn't impede the American assault on a peasant nation; a single image that made it a visceral reality to millions - many of whom don't read contexts, or anything much else - did.
Flailing accusations of 'tragedy-porn', IMHO, also display a rather shabby dismissal of the work of a body of men - and some women - who overwhelmingly did an important job for all the right reasons, 135 of whom lost their lives in Indochina doing it.