Work on Shabbat - Rabbis

Question

In your reponse to the question about "Jews in Sports", you wrote that he's working on Shabbat, which is not allowed. Is this any different than a Rabbi, whose main service towards the synagogue is service on Shabbat. If anything, its worse... To the ballplayer, the Shabbat game is the same as any other. To the Rabbi, he can pretty much take off any day without upsetting too many people EXCEPT for Shabbat. People have told me before that it's ok because "technically" the Rabbi gets paid for his work during the week, and the stuff he does on Shabbat he does not get paid for. Common, who are we kidding? If that were the truth, they'd be entitled to take every Shabbat off without punishment (legally). God cannot be this shortsighted and naive. Please provide me with a more insightful answer!