It's not just a semantic distinction. The game was originally conceived as part of the 1933 World's Fair in Chicago, and the idea was to showcase the best players -- the Stars -- of the day.
So how do you know who's a Star? Bill James nailed this 23 years ago:
The Toby-Harrah-for-the-All-Star-team controversy... how can the entire country get so confused about these things? Let's review the facts: Toby Harrah plays in the major leagues for roughly 40 years, during which he clearly and unmistakably establishes that he is not an All-Star. George Brett, over a period of several years, establishes beyond any shadow of a doubt that he is an All-Star. Toby Harrah has a hot streak early in the year, on the strength of which he carries a .336 batting average into the All-Star break with 17 home runs and 45 RBI, while George Brett was stumbling along barely over .300 with only 10 homers. Nevertheless, the nation's baseball fans elect George Brett to the All-Star team, which strikes me as an act of abundant good sense, because everybody in the country knows that George Brett is a better ballplayer than Toby Harrah.Etc.
But what comes of this? Why do we have to put up, every All-Star season, with these asinine editorials about why is this guy on the All-Star team . . . Was there one of you out there who really thought that Toby Harrah became a .336 hitter? And if you didn't think that he was a .336 hitter, why did you think that he should have been on the All-Star team? Would you be happy if we scheduled an All-Mediocrities-Who-Had-Good-First-Halves Game? We could play it in Cleveland every year.
And yet, sure enough, I open up the sports section of the local newspaper the other day, and there's the baseball columnist moaning that, sure, Roy Oswalt's a better pitcher, a bigger name, and, yes, a Star, but he only has 6 wins, while some guy named Chris Young (who?) and some other guy named Chris Capuano (who??) have 7 and 10, respectively. Or something. I'm sure there are other examples in other newspapers using other players. It happens every year.
Back to Bill James:
There is a debate that goes along with this every June and July about the "relevance" of this season's statistics and the "relevance" of career statistics to the question of who belongs in the All-Star Game. I can see how this would be a difficult issue to resolve, particularly if you haven't stopped to think about the subject for thirty-five seconds before joining the debate. If you have, the resolution of the debate is absurdly obvious.This is why lawyers love Bill James. He saw his job as asking, "What is the evidence, and what does it mean?"
Q. What are baseball statistics? What do they mean?
A. Baseball statistics are valuable as evidence about the ability of baseball players.
Q. Why do we keep them?
A. We keep them to tell us how good a baseball player somebody is.
Q. Which statistics are relevant to the selection of an All-Star team?
A. All statistics are relevant to the extent that they provide credible evidence about the abilities of the player involved.