David Gerrold's announcement that he will unfriend the majority of Americans who support Donald Trump for president is a clear example of why it makes no sense to attempt to be friends with SJWs or even be civil with them. Time and time and time again, I see someone explain that so-and-so SJW "is really a good guy" or that this-and-that SJW "is fine as long as we don't discuss politics".
But politics is all-consuming for the SJW, and when push comes to shove, the SJW will ALWAYS choose his politics over you because his politics are an intrinsic aspect of his personal identity. You might as reasonably expect him to cut off a body part in order to preserve the relationship once the inevitable conflict arrives. The SJW is not your friend. The SJW is incapable of being your friend.
So don't associate with SJWs. Don't cut them any slack at all. Once a friend, a family member, or an acquaintance reveals symptoms of SJW, you should quarantine them as ruthlessly as you would quarantine them if they had ebola or some other lethal and infectious disease.
Be the problem.