I don't think posting the same information again and again is welcome. The people who might be inspired to debate it simply can't have a discussion about it every time it appears - and it goes beyond wanting to engage with the community and share something and becomes an attempt to manipulate. I'd certainly encourage tokenadult to stop posting it.
If this were a wiki or answers site, where you want one easy-to-find location for a given piece of relevant content, I think you'd be correct.
On a link stream + discussion style site (which HN appears to be), though, you don't really have any idea who's participating at any given moment, or who's seen/absorbed material from previous discussions. I've been reading HN on/off for about 3 years, I can only recall having seen this once before, and seeing it again is an interesting reminder.
Apparently others have seen it a few times and are tired of it, but by and large, I'd think the scoring system could handle the general opinion of the community pretty sell: if enough readers still find it to be new/interesting information, it'll stay highly visible. If readers are tired of seeing it, presumably it'll sink to the bottom.
I haven't seen this comment before and took something useful from it, so it seems ok to repost it. Your suggestion to link to the previous posting and it's discussion seems like the best approach.