I think it was meant as a pun based on the poster's monicker "PlanetEminem." You advertised a "Christian league" and Eminem says "no thanks." Not a great attempt a humor, but that was what I think he might have been trying to do, rather than an actual insult against your league.
BTW, I used to go through Safeway muttering "yes," "no," and "AH! That tomato is trying to kill me!!!" But, I am better now... at least when I remember to take the Zoloft...