Earlier quoted context omitted.
I suspect it's because they didn't/don't want people to comment in the usual way - you can highlight text on an article and leave short comments in the relevant place if you want to do that. I think the comments section at the end was intended more as a place for lengthy reaction posts. It's why comments have "recommend" rather than "like" as a button. I might "like" someone saying "great post!" but I'm not going to…
Commenting on articles is a terrible method of interaction. Anti-spam is hard, and spammers always win. Trolls always win. Comments rarely add much to the discussion from the article, and they're often hard to follow. There's no reason to leave a comment saying "great post!". It's spam. It's unnecessary. Blogs are a wholly inappropriate place for back-and-forth discourse to happen simply because if I have a blog, it'…
I'm sure moderating comments is hard. But when it's done well comments are great.