As is so often the case, Quora’s policy is vague enough to need interpretation, and this is a question that I welcome Christopher VanLang’s feedback to.
The chapter and verse is:
Blogs on Quora are generally unmoderated. Most policies that apply to question-and-answer pages do not apply to blogs.
The catch is,
1. Blogs whose primary purpose is to attack, insult, and/or derogatorily label people are not allowed.
That appears to me to be a higher bar than BNBR: there is, I would think, some breathing room between “nice” and “attack”, and there is some room between “blog whose primary purpose is to attack” and “occasional post which attacks”. But I don’t know what the test cases have been.
2. Blogs which aren’t aimed at attacking people but still have a purpose of attacking content will no longer generate notifications or repost trackbacks.
Which means that attacking bad content is allowed, it’s just not particularly facilitated.