Well, as I see it, for the large majority of visible SJW types, their causes are LGBT rights, feminism, veganism, X-shaming, positive-X-image, and so on.
That is, (some token pro-black/immigrant activism aside, when it's comfortable) more or less non-problems, in an age where the respective groups never had it better and acceptance of them was never more in vogue and established (from Hollywood to major news outlets to laws).
Judging from 99% of their public output, most SJW could not care less for the vast numbers of homeless, the battered middle and working classes, for prison conditions. In fact the same "good souls" would go and openly mock "white trash" -- and they'd do the same for the "latino/black trash" if it wasn't frowned upon.
The difference between real societal issues and SJW causes, is that the former are cross cutting (across niches of people) and fundamental, while the latter are trendy and for the most part inconsequential today (when they don't get into the bizarro, e.g. the "cotton ceiling" thing).
Only a small brave minority fought for gay rights in the 60s and 70s, when gay was a dirty word. But now that it's in fashion, everybody fights the "token" gay fight, for ever more inconsequential rights. It's almost as if they're not pro-LGBT, they just take the winning side, and use it to prop their bios and popularity.