All-Star voting in real life in sports is not a perfect system where you see people whom don't deserve be named starter over a guy backing them up, or sometimes a guy gets snubbed. It is a quite frequent thing across all sports' all-star voting, course when fans vote, they just vote for their favorite players rather than those whom deserve it...
Baseball's asg was most recent so I'll use it. David Wright, had higher in every statistical category than Pablo Sandoval, but was his backup, despite hitting .050 higher, 4 more hr, 11 more sb, 30+ more RBI 20+ more runs.
Andrew McCutchen, whom I would say with his MLB best BA and the Pirates in 1st place at the time, was front-runner for MVP, was backing up Melky Cabrera... from SF, whom all he had was the 2nd best BA in baseball, behind McCutchen, and some SB.