I think you're being a little unfair about #9. Setting boundaries is different to ignoring challenges. If I made a comment about politics and someone demanded that I present a solid case that black people have ever been mistreated, obviously it's fine to ignore. It's tangential and agenda-driven, just like the example in OP.
Some conflicts are simply not worth pursuing. Even Bertrand Russell refused to debate Oswald Mosley.
In the Internet, we have built an unlimited stream of information. You could quit your job and do nothing but post and reply full-time, and you'd never get near being able to respond to every commenter if everyone who read what you wrote chose to comment.
Filtering signal from noise is a vital skill in the online era. And sure, if your filter is over-tight you'll end up in an echo chamber... But as there's no penalty for being wrong on the Internet, a healthy filter is downsampling a lot of information these days.
OK I see. Well, my input is that it goes beyond editorialisation to misrepresentation for the reasons I outline above! Imo enforcing appropriate boundaries is good for one's mental health and relationships. And I think the boundary she describes - ignoring tangential, agenda-driven comments - is absolutely appropriate.
Some conflicts are simply not worth pursuing. Even Bertrand Russell refused to debate Oswald Mosley.