The actual reason he wasn't given a medal was that Carrie Fisher couldn't reach, and they didn't want to have him kneel to get the medal when no one else did. In the expanded universe they have explained that Wookies don't believe in getting medals or trophies for doing things that needed to be done.
While on vacation one time as a wee child, instead of doing vacationy things, I made Dad take me down to the front office where you could rent VHS tapes and made him rent Star Wars. I'd already seen it like twelve times.
Then I spent the rest of the trip playing my SNES.