It makes NO sense!!!
Why go to Mail if you're just going to link back to Safari?
There is absolutely NO reason why Safari should use Mail to hold its RSS links.
I tried Google Reader and it seriously *****, very difficult to use and the formatting and interface is terrible. I spent 10 minutes and STILL could not find any way to add the feeds I wanted. I just kept on seeing their "Reccomended" articles, which I could NEVER DELETE!
The "RSS Extensions" for Safari are ALL just lame Google Reader extensions. If Apple had just a simple RSS reader extension on their site, none of this would be happening. You are FORCED to use a Google Reader extension if you want to stay in Safari.
What was so incredibly vital that RSS had to be ripped from Safari's code?
Money!
By using RSS you bypass all of the innane advertising. I see no other reason than Google making some sort of deal with Apple. This way Google can continue to track your actions and display the ads they want you to see.
I see absolutely no reason or advantage in keeping the POS Safari 6. As soon as I find an easy way to get the old one back, I'll post it here.