Since we had this discussion before, I wanted to show more statistics.
2004-2005 NBA Fouls Per Game
Jermane O'Neal is #4.
Shaq is #10 and Yao Ming is #9
All the players in the top #10 with the highest foul totals per game were either forwards or centers.
The highest ranked guard was Steve Francis at #12. You look down to the top 50 and you see more and more centers and forwards with the highest total.
I am sure if someone did a study they would find similar totals over the years. You really do not see many fouls are called by the officials on the perimeter, but near the basket. Who is most likely to be near the basket and attempt to block shots? You got it, centers and forwards. Not 6'2" guards who are defending other guards.
Peace