I agree with you that Medium's labor force could be a limiting factor here.

On the other hand, it's my understanding that Medium already has employees manually reviewing posts and comments that are reported as abuse under the current rules - not to mention reviewing most new stories, to flag them as recommendation-worthy. I also think most reportable posts and comments go unreported - ie people just respond or block and deal with them on their own, and I think Medium probably relies on this so as not to get inundated with to many reports to review.

My guess is that adding these new rules would not actually increase the number of reports by all that much. But having them stated clearly as rules would, I think improve the quality of writing and commenting on Medium.

Contrary to what you say, I don't think most people are capable of addressing these arguments in appropriate ways. I've seen too many comment threads go off the rails to believe that. Society in general would be in a very different place if people were capable of cunducting constructive conversations without a moderator enforcing good rules. Medium is our moderator. And I think there is quite a bit of room for improvement in how and which rules they enforce.