The meme of "if you don't speak up, you're complicit" is part of this.
I appreciate the sentiment, but there are just too many (terrible!) inequities in the world to live by this and not have it be a full time preoccupation.
Also, is social media really the best way to take action against terrible inequity? I would think if one believes the uninvolved are complicit, they would also look for more effective methods than saying something is bad on Twitter.