It's not ideal, but your argument could just as much apply to other sports. The team with home field advantage throughout the playoffs in one of the NFL conferences, for example, could have won it because of being in a weak division. Although not perfect, I think it is more justifiable to determine home field advantage based on best record rather than deciding whether the Mets or Tigers, for example, get home field advantage based on what players from other teams do in the All-Star game.