the reward pool does not enter into the intellectual or creative property of the content in any way.

Yes of course that is true. Property of the content itself is a separate matter to rewarding it out of the common reward pool. Being able to reply (and not being blocked by the poster) as to why content may be more or less worthy of rewards is an important process. The points about @cheetah and @steemcleaners are a subset of this but any stakeholder may have valuable information about why the post may not be worthy of rewards, and letting the poster unilaterally hide that seems problematic.

Posters can always downvote comments they don't like but then it becomes a community decision (by others voting as well) whether those are hidden, which seems right to me when those comments are discussing the posts value or lack thereof for reward purposes.

As Steemit.inc says in the post, its their call what to implement, if someone else wants to create a frontend with their own rules they can....

Certainly true. I'm giving my view on what seems best for the integrity of the reward pool and avoiding abuses, which is something they very much care about, as evidenced by both quoting of @anyx's comments in their follow-on post as well as their work on EIP in HF21.

If we are going to move away from a community reward pool as some have suggested, then it becomes less of an issue and the discussion threads can reasonably start to be viewed as the private domain of the blogger to filter and moderate as they see fit. But until and unless that happens (which isn't the case now or in the imminent HF21) I don't believe that should be the case.