dang, as many others have pointed out very well, pg's post contains "low quality," and in my view inflammatory comments. You refuse to call him out on it, not a peep at all. Instead, you call out others for responding in disagreement. Would you apply the "Principle of Charity" to the remarks of those that you think to be low quality? If not, can you justify why the "Principle of Charity" should not apply to pg but to everyone else who disagrees with him?
You say, "the onus is on all of us to contribute substantively even in response to something we consider unsubstantive." How about the responsibility of the original poster? Is it acceptable to write that way? Can he be legitimately criticized for that? If you don't accept that, then you've created an unfair situation.
(regarding your refusal to criticize pg) "I think that would be a mistake"
The real mistake is the way you try to shut down dissent by painting it as "uncharitable" or misguided/mistaken. Can you point out the many examples of "much of this thread is of low quality" ? I don't think you can make that case, because it seems that you disagree with the opinions more than anything else.
Some of the dissenting opinions are passionate. And there is nothing wrong with that. Just look at pg's original post, there is a lot of passion there. I would suggest that you be an adult and understand that there are controversial topics which will cause passionate discussion. It makes no sense to a accuse everyone of being wrong in their interpretation and to scold them as if they're children. Just read the comments and you'll see that a lot of people here have unique knowledge and understanding of the topic. Your point is incorrect, and adds nothing to this very important (and passionate) subject.