I didn't get that comment either. I've doubled-down on RSS for this purpose in my side-project Haven[1]. Write your own private blog, share it with people who can then subscribe with personal http-basic-auth RSS links (or view it on the web), and I've recently built in (still a WIP) a feed reader so you can create your own facebook-style news feed of anything on the web or things your friends write privately on their own Haven.
Maybe they mean that since there are many different feed readers a person could use, a blog can't have a "Click here to subscribe via RSS" link? Most feed readers will have a bookmarklet for 1-click subscribing, but the blog owner doesn't have the ability to make a prominent "call to action"-style button.
Sure they can, well they can have a link that brings up the feed anyway. What the browser does with it is a different story, and that depends on whether RSS preview extensions are installed. Copying and pasting that URL wherever it needs to go isn't all that complicated.
