Great points! For just a small contrary take, I have large followings on Twitter and Facebook, where I promote my writing pretty heavily. The Twittersphere especially is a pretty hostile space, and I write about LGBTQ issues mostly, which are inherently controversial.
I don’t block a lot on Faceblock, but I block liberally on Twitter. I don’t do it because I’m angry (well, not usually.) I do it because I need to find a balance between writing and promoting. The more I let naysayers trash my work on Twitter, the more I’m apt to get drawn in and waste my time.
So I block, instead, when the comments are just thoughtless hate.
Saves me time and lets me actually do what I love, which is write stories.