No, he isn't being pedantic. It's a real, valid usability issue.
"783 days and 4 hours ago" really is worse. If I am browsing a photo and look at that, my first reaction is "That photo was taken a long time ago". If my buddy asks when that happened, I'll have to start doing some simple math in my head. "Uhh, around two years ago? So what, that's 2010?"
Simply putting the date would have been a much friendly solution. You know immediately that it was "a long time ago" because everyone knows what the current year is. And you know what year immediately.
Conversely, on short scales it's opposite. I don't really care if a post was on Monday or Tuesday (usually). I care that it was recent. Providing the exact timestamp doesn't help.
Both have their uses.
