No, the Olympics committee didn't misspell House Stark's second son's surname: Starc is an acclaimed high jumper from Australia. And we can't help but notice he bears a passing resemblance to Isaac Hempstead Wright, the young actor who portrays his Thrones namesake.
Starc too knows what it's like to constantly get overshadowed by a big bro, thanks to his older sibling, the famous cricketer Mitchell Starc. Even where the Olympics are concerned, Brandon Starc is hardly the first of his name: there have been 13 Starks spread across seven countries throughout the history of these Games. (It's also worth noting that House Tully has seen a decent Olympic showing as well, from six different competitors; no Hodors or Wylises, though.)