Yes the all star game is just for fun, but even then the teams still try to win the game. Even in the NBA you see this. How many times have you seen that a player is voted in by the fans but actually plays less minutes in the game then the league selected backup player?
At the end of the day, as long as it remains just for fun then it is fine, but once people start wanting to have financial tie ins with the all star games, then the current format and selection process of the all star game is just not acceptable as the selection process is a crapshoot.