I tend to agree with the user who defended summary comments on the basis of the utility of top-comments to decide whether the article is worth reading. If people consider summary comments to be a non-positive addition to HN discussion threads then I would hope this can be resolved by the normal down-vote process rather then through special measures.

Any reason that HN doesn't have a meta and way to visualize show that a submission/comment has meta related content tied to it?

I'm not sure I follow, but the answer is probably that it would complicate things.