In my experience HN is not made for discussions except if one is the main person concerned by the post.
I actually prefer editing my comment instead of replying to not bloat the discussion, but I think most people just don't reply either because they don't check the replies (very likely) and/or do not want to engage in a public discussion/debate/flamewar.
Also on HN there is a sense that an opinion does not belong to someone hence why other people can (and are encouraged) to respond to criticism in place of the parent.
In my experience HN is not made for discussions except if one is the main person concerned by the post.
I actually prefer editing my comment instead of replying to not bloat the discussion, but I think most people just don't reply either because they don't check the replies (very likely) and/or do not want to engage in a public discussion/debate/flamewar.