Yes, really. I'd consider all the things you listed, even the ones I have no interest in, more worthwhile than spending one's time making screencaps of blog posts in case someone decides to remove them. Do these people who are doing screencaps of everything also walk around constantly with voice recorders in case anyone says anything they want to bring up later?

"Hold people to account for their actions"? Their "actions" are just comments in a blog. Posting a blog is like having a physical diary and showing it to people. You can shut it (or part of it) any time you like. And, you know, sometimes it's better that way.