I believe the issue is the type of discussions that can damage the fabric of the website. Repetitive discussions on tech products are not good but can't damage the site. But discussions of politics can be inflammatory and repetitive inflammatory discussions could damage the site since it dampens intellectual curiosity of people overall. I'm not a moderator or anything so I don't know but that's just my guess based on what dang has said in previous comments.
A lot of repetitive discussions of tech things get moderated all the time as well, you can just email them in and the moderators sort them out. There's a lot of mod commentary on how things like releases, feature updates, 'launch week' etc are handled, one recent example
https://news.ycombinator.com/item?id=43129444