because the browser is supposed to provide the button.
Why do you think I’m worried? I don’t want to have to clutter my site with a button to an XML feed that nobody understands. I want the browser auto-discovery to do the right thing and present the right interface to make RSS worthwhile.
Turning the key in a car shouldn’t present you a diagram on how to connect the battery. Browsers shouldn’t sit there dumbfounded when presented a piece of RSS.
Your analogy doesn't work for me. A car is built to run when you turn it on. That is basic functionality. The reverse analogy to a browser would be "making an HTTP request shouldn't present you a diagram on how to do DNS resolution," and the browser doesn't.
If I copy the URL of your site/blog into my RSS reader's Add Subscription dialog, I don't know of any RSS readers that wouldn't scrape your site for the link tags I assume you put in and discover the feed for me.
You can take his concern seriously, RSS autodiscovery in FF is working fine on his page. And that's the feature the author would like to keep in the future.