I don’t want to come across as an apologist for the author, but I can imagine him replying that this is an intentional trade off, and that for a larger-scale conversation about the work, the mailing list is a better option.
I’ll concede that at that point, a mailing list may be preferable to the RSS feed in the first place. Or Usenet.
So if someone's feed extols the virtues of RSS feeds the only option for sharing that is to share the whole feed. If someone checks the feed a month later that great point made may no longer be in the feed. Since it doesn't exist as a post on a website it's just lost. No no one will ever be convinced RSS is the end-all be-all of blogging.